Add values command (see #7166)

[webbedspace]

Description

This adds a counterpart to columns called values (see #7166 for name motivation). This can be combined with each to iterate over the values of a record (which is useful when the record is holding homogenous data). When given a table, it produces a list of columns (list of lists). Holes are not preserved (for obvious reasons).

This differs slightly from columns in that it will error if given a non-record non-table.

User-Facing Changes

See above.

Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

• cargo fmt --all -- --check to check standard code formatting (cargo fmt --all applies these changes)
• cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect to check that you're using the standard code style
• cargo test --workspace to check that all tests pass

After Submitting

If your PR had any user-facing changes, update the documentation after the PR is merged, if necessary. This will help us keep the docs up to date.

[fdncred]

Nice work!

One thing that kind of jumps out at me is the name of the command. I'm not asking for a change but I think about it like this. keys and values go together. columns and values seems different. And then since nushell is built on the Value enum, I wonder if people get confused that values could mean spitting out the nushell Value enum representation? Of course, end users may have no clue that nushell is built on an enum Value, so it may not make any difference. Just thinking out loud.

[stormasm]

@fdncred I would like to go ahead and land this one...
Or you can do it...
This is going to be helpful for me right now with the
Arrow RecordBatch

[fdncred]

You got it @stormasm. Thanks @webbedspace