Remove math eval command (#7284)

Reasoning: 

Most missing math commands are implemented with #7258.
The `meval` crate itself declares that it doesn't strive to stringent
standards (https://docs.rs/meval/latest/meval/#related-projects).
For example no particular special casing or transformations are
performed to ensure numerical stability. It uses the same rust `std`
library functions we use or have access to (and `f64`).
While the command call syntax in nushell may be a bit more verbose,
having a single source of truth and common commands is beneficial.
Furthermore the `math` commands can themselves implement broadcasting
over lists (or table columns).

Closes #7073

Removed dependencies:
- `meval`
- `nom 1.2.4` (duplicate)

User-Facing Changes:

Scripts using `math eval` will break. 
We remove a further `eval` like behavior to get results through runtime evaluation (albeit limited in scope)

Tests:

- Updated tests that internally used `math eval`.
- Removed one test that primarily used `math eval` to obtain a result from `str join`

crates/nu-command/tests/commands/math/mod.rs

@@ -1,5 +1,4 @@
 mod avg;
-mod eval;
 mod median;
 mod round;
 mod sqrt;