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}`.

benches/benchmarks.rs

@@ -114,13 +114,14 @@ fn eval_benchmarks(c: &mut Criterion) {
 
 // generate a new table data with `row_cnt` rows, `col_cnt` columns.
 fn encoding_test_data(row_cnt: usize, col_cnt: usize) -> Value {
-    let columns: Vec<String> = (0..col_cnt).map(|x| format!("col_{x}")).collect();
-    let vals: Vec<Value> = (0..col_cnt as i64).map(Value::test_int).collect();
+    let record = Value::test_record(
+        (0..col_cnt)
+            .map(|x| (format!("col_{x}"), Value::test_int(x as i64)))
+            .collect(),
+    );
 
     Value::List {
-        vals: (0..row_cnt)
-            .map(|_| Value::test_record(columns.clone(), vals.clone()))
-            .collect(),
+        vals: vec![record; row_cnt],
         span: Span::test_data(),
     }
 }