Move more commands to opaque Record type (#11122)

# Description

Further work towards the goal that we can make `Record`'s field private
and experiment with different internal representations

## Details
- Use inplace record iter in `nu-command/math/utils`
  - Guarantee that existing allocation can be reused
- Use proper record iterators in `path join`
- Remove unnecesary hashmap in `path join`
  - Should minimally reduce the overhead
- Unzip records in `nu-command`
- Refactor `query web` plugin to use record APIs
- Use `Record::into_values` for `values` command
- Use `Record::columns()` in `join` instead.
  - Potential minor pessimisation
  - Not the hot value path
- Use sane `Record` iters in example `Debug` impl
- Avoid layout assumption in `nu-cmd-extra/roll/mod`
  - Potential minor pessimisation
- relegated to `extra`, changing the representation may otherwise break
this op.
- Use record api in `rotate`
- Minor risk that this surfaces some existing invalid behavior as panics
as we now validate column/value lengths
  - `extra` so things are unstable
- Remove unnecessary references in `rotate`
  - Bonus cleanup
# User-Facing Changes
None functional, minor potential differences in runtime. You win some,
you lose some.

# Tests + Formatting
Relying on existing tests

crates/nu-cmd-lang/src/example_support.rs

@@ -233,13 +233,12 @@ impl<'a> std::fmt::Debug for DebuggableValue<'a> {
             }
             Value::Record { val, .. } => {
                 write!(f, "{{")?;
-                for i in 0..val.len() {
-                    let col = &val.cols[i];
-                    let value = &val.vals[i];
-
-                    if i > 0 {
+                let mut first = true;
+                for (col, value) in val.into_iter() {
+                    if !first {
                         write!(f, ", ")?;
                     }
+                    first = false;
                     write!(f, "{:?}: {:?}", col, DebuggableValue(value))?;
                 }
                 write!(f, "}}")