Create Record type (#10103)

# Description
This PR creates a new `Record` type to reduce duplicate code and
possibly bugs as well. (This is an edited version of #9648.)
- `Record` implements `FromIterator` and `IntoIterator` and so can be
iterated over or collected into. For example, this helps with
conversions to and from (hash)maps. (Also, no more
`cols.iter().zip(vals)`!)
- `Record` has a `push(col, val)` function to help insure that the
number of columns is equal to the number of values. I caught a few
potential bugs thanks to this (e.g. in the `ls` command).
- Finally, this PR also adds a `record!` macro that helps simplify
record creation. It is used like so:
   ```rust
   record! {
       "key1" => some_value,
       "key2" => Value::string("text", span),
       "key3" => Value::int(optional_int.unwrap_or(0), span),
       "key4" => Value::bool(config.setting, span),
   }
   ```
Since macros hinder formatting, etc., the right hand side values should
be relatively short and sweet like the examples above.

Where possible, prefer `record!` or `.collect()` on an iterator instead
of multiple `Record::push`s, since the first two automatically set the
record capacity and do less work overall.

# User-Facing Changes
Besides the changes in `nu-protocol` the only other breaking changes are
to `nu-table::{ExpandedTable::build_map, JustTable::kv_table}`.

crates/nu-command/src/platform/dir_info.rs

@@ -1,6 +1,6 @@
 use filesize::file_real_size_fast;
 use nu_glob::Pattern;
-use nu_protocol::{ShellError, Span, Value};
+use nu_protocol::{record, ShellError, Span, Value};
 use std::path::PathBuf;
 use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
@@ -185,30 +185,6 @@ impl DirInfo {
 
 impl From<DirInfo> for Value {
     fn from(d: DirInfo) -> Self {
-        let mut cols = vec![];
-        let mut vals = vec![];
-
-        cols.push("path".into());
-        vals.push(Value::string(d.path.display().to_string(), d.tag));
-
-        cols.push("apparent".into());
-        vals.push(Value::Filesize {
-            val: d.size as i64,
-            span: d.tag,
-        });
-
-        cols.push("physical".into());
-        vals.push(Value::Filesize {
-            val: d.blocks as i64,
-            span: d.tag,
-        });
-
-        cols.push("directories".into());
-        vals.push(value_from_vec(d.dirs, d.tag));
-
-        cols.push("files".into());
-        vals.push(value_from_vec(d.files, d.tag));
-
         // if !d.errors.is_empty() {
         //     let v = d
         //         .errors
@@ -223,51 +199,34 @@ impl From<DirInfo> for Value {
         //     })
         // }
 
-        Value::Record {
-            cols,
-            vals,
-            span: d.tag,
-        }
+        Value::record(
+            record! {
+                "path" => Value::string(d.path.display().to_string(), d.tag),
+                "apparent" => Value::filesize(d.size as i64, d.tag),
+                "physical" => Value::filesize(d.blocks as i64, d.tag),
+                "directories" => value_from_vec(d.dirs, d.tag),
+                "files" => value_from_vec(d.files, d.tag)
+            },
+            d.tag,
+        )
     }
 }
 
 impl From<FileInfo> for Value {
     fn from(f: FileInfo) -> Self {
-        let mut cols = vec![];
-        let mut vals = vec![];
-
-        cols.push("path".into());
-        vals.push(Value::string(f.path.display().to_string(), f.tag));
-
-        cols.push("apparent".into());
-        vals.push(Value::Filesize {
-            val: f.size as i64,
-            span: f.tag,
-        });
-
-        cols.push("physical".into());
-        vals.push(Value::Filesize {
-            val: match f.blocks {
-                Some(b) => b as i64,
-                None => 0i64,
-            },
-            span: f.tag,
-        });
-
-        cols.push("directories".into());
-        vals.push(Value::nothing(Span::unknown()));
-
-        cols.push("files".into());
-        vals.push(Value::nothing(Span::unknown()));
-
         // cols.push("errors".into());
         // vals.push(Value::nothing(Span::unknown()));
 
-        Value::Record {
-            cols,
-            vals,
-            span: f.tag,
-        }
+        Value::record(
+            record! {
+                "path" => Value::string(f.path.display().to_string(), f.tag),
+                "apparent" => Value::filesize(f.size as i64, f.tag),
+                "physical" => Value::filesize(f.blocks.unwrap_or(0) as i64, f.tag),
+                "directories" => Value::nothing(Span::unknown()),
+                "files" => Value::nothing(Span::unknown()),
+            },
+            f.tag,
+        )
     }
 }