Msgpack commands (#12664)

# Description

I thought about bringing `nu_plugin_msgpack` in, but that is MPL with a
clause that prevents other licenses, so rather than adapt that code I
decided to take a crack at just doing it straight from `rmp` to `Value`
without any `rmpv` in the middle. It seems like it's probably faster,
though I can't say for sure how much with the plugin overhead.

@IanManske I started on a `Read` implementation for `RawStream` but just
specialized to `from msgpack` here, but I'm thinking after release maybe
we can polish it up and make it a real one. It works!

# User-Facing Changes
New commands:

- `from msgpack`
- `from msgpackz`
- `to msgpack`
- `to msgpackz`

# Tests + Formatting
Pretty thorough tests added for the format deserialization, with a
roundtrip for serialization. Some example tests too for both `from
msgpack` and `to msgpack`.

- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`


# After Submitting
- [ ] update release notes

crates/nu-command/tests/format_conversions/msgpackz.rs

@@ -0,0 +1,28 @@
+use nu_test_support::nu;
+use pretty_assertions::assert_eq;
+
+#[test]
+fn sample_roundtrip() {
+    let path_to_sample_nuon = nu_test_support::fs::fixtures()
+        .join("formats")
+        .join("msgpack")
+        .join("sample.nuon");
+
+    let sample_nuon =
+        std::fs::read_to_string(&path_to_sample_nuon).expect("failed to open sample.nuon");
+
+    let outcome = nu!(
+        collapse_output: false,
+        format!(
+            "open '{}' | to msgpackz | from msgpackz | to nuon --indent 4",
+            path_to_sample_nuon.display()
+        )
+    );
+
+    assert!(outcome.status.success());
+    assert!(outcome.err.is_empty());
+    assert_eq!(
+        sample_nuon.replace("\r\n", "\n"),
+        outcome.out.replace("\r\n", "\n")
+    );
+}