Add multipart/form-data uploads (#13532)

Fixes nushell/nushell#11046

# Description
This adds support for `multipart/form-data` (RFC 7578) uploads to
nushell.

Binary data is uploaded as files (`application/octet-stream`),
everything else is uploaded as plain text.

```console
$ http post https://echo.free.beeceptor.com --content-type multipart/form-data {cargo: (open -r Cargo.toml | into binary ), description: "It's some TOML"} | upsert ip "<redacted>"
╭───────────────────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ method            │ POST                                                                                                                                                                    │
│ protocol          │ https                                                                                                                                                                   │
│ host              │ echo.free.beeceptor.com                                                                                                                                                 │
│ path              │ /                                                                                                                                                                       │
│ ip                │ <redacted>                                                                                                                                                              │
│                   │ ╭─────────────────┬────────────────────────────────────────────────────────────────────╮                                                                                │
│ headers           │ │ Host            │ echo.free.beeceptor.com                                            │                                                                                │
│                   │ │ User-Agent      │ nushell                                                            │                                                                                │
│                   │ │ Content-Length  │ 9453                                                               │                                                                                │
│                   │ │ Accept          │ */*                                                                │                                                                                │
│                   │ │ Accept-Encoding │ gzip                                                               │                                                                                │
│                   │ │ Content-Type    │ multipart/form-data; boundary=a15f6a14-5768-4a6a-b3a4-686a112d9e27 │                                                                                │
│                   │ ╰─────────────────┴────────────────────────────────────────────────────────────────────╯                                                                                │
│ parsedQueryParams │ {record 0 fields}                                                                                                                                                       │
│                   │ ╭─────────────────┬───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮ │
│ parsedBody        │ │                 │ ╭─────────────┬────────────────╮                                                                                                                  │ │
│                   │ │ textFields      │ │ description │ It's some TOML │                                                                                                                  │ │
│                   │ │                 │ ╰─────────────┴────────────────╯                                                                                                                  │ │
│                   │ │                 │ ╭───┬───────┬──────────┬──────────────────────────┬───────────────────────────┬───────────────────────────────────────────┬────────────────╮      │ │
│                   │ │ files           │ │ # │ name  │ fileName │       Content-Type       │ Content-Transfer-Encoding │            Content-Disposition            │ Content-Length │      │ │
│                   │ │                 │ ├───┼───────┼──────────┼──────────────────────────┼───────────────────────────┼───────────────────────────────────────────┼────────────────┤      │ │
│                   │ │                 │ │ 0 │ cargo │ cargo    │ application/octet-stream │ binary                    │ form-data; name="cargo"; filename="cargo" │ 9101           │      │ │
│                   │ │                 │ ╰───┴───────┴──────────┴──────────────────────────┴───────────────────────────┴───────────────────────────────────────────┴────────────────╯      │ │
│                   │ ╰─────────────────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯ │
╰───────────────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
```
# User-Facing Changes
`http post --content-type multipart/form-data` now accepts a record
which is uploaded as `multipart/form-data`.
Binary data is uploaded as files (`application/octet-stream`),
everything else is uploaded as plain text.

Previously `http post --content-type multipart/form-data` rejected
records, so there's no BC break.

# Tests + Formatting

Added.

# After Submitting
- [ ] update docs to showcase new functionality

crates/nu-command/tests/commands/network/http/post.rs

@@ -1,4 +1,4 @@
-use mockito::Server;
+use mockito::{Matcher, Server, ServerOpts};
 use nu_test_support::{nu, pipeline};
 
 #[test]
@@ -197,3 +197,34 @@ fn http_post_redirect_mode_error() {
         "Redirect encountered when redirect handling mode was 'error' (301 Moved Permanently)"
     ));
 }
+#[test]
+fn http_post_multipart_is_success() {
+    let mut server = Server::new_with_opts(ServerOpts {
+        assert_on_drop: true,
+        ..Default::default()
+    });
+    let _mock = server
+        .mock("POST", "/")
+        .match_header(
+            "content-type",
+            Matcher::Regex("multipart/form-data; boundary=.*".to_string()),
+        )
+        .match_body(Matcher::AllOf(vec![
+            Matcher::Regex(r#"(?m)^Content-Disposition: form-data; name="foo""#.to_string()),
+            Matcher::Regex(r#"(?m)^Content-Type: application/octet-stream"#.to_string()),
+            Matcher::Regex(r#"(?m)^Content-Length: 3"#.to_string()),
+            Matcher::Regex(r#"(?m)^bar"#.to_string()),
+        ]))
+        .with_status(200)
+        .create();
+
+    let actual = nu!(pipeline(
+        format!(
+            "http post --content-type multipart/form-data {url} {{foo: ('bar' | into binary) }}",
+            url = server.url()
+        )
+        .as_str()
+    ));
+
+    assert!(actual.out.is_empty())
+}