Break up interdependencies of command crates (#9429)

# Description
Make sure that our different crates that contain commands can be
compiled in parallel.
This can under certain circumstances accelerate the compilation with
sufficient multithreading available.

## Details
- Move `help` commands from `nu-cmd-lang` back to `nu-command`
- This also makes sense as the commands are implemented in an
ANSI-terminal specific way
- Make `nu-cmd-lang` only a dev dependency for `nu-command`
- Change context creation helpers for `nu-cmd-extra` and
`nu-cmd-dataframe` to have a consistent api used in
`src/main.rs`:`get_engine_state()`
- `nu-command` now indepedent from `nu-cmd-extra` and `nu-cmd-dataframe`
that are now dependencies of `nu` directly. (change to internal
features)
- Fix tests that previously used `nu-command::create_default_context()`
with replacement functions

## From scratch compilation times:

just debug (dev) build and default features
```
cargo clean --profile dev && cargo build --timings
```

### before

![grafik](https://github.com/nushell/nushell/assets/15833959/e49f1f42-2e53-4a6c-bc23-625b686af1bc)

### after

![grafik](https://github.com/nushell/nushell/assets/15833959/8dec4723-e625-4a86-b91e-e6e808f64726)

# User-Facing Changes
None direct, only change to compilation on multithreaded jobs expected.

# Tests + Formatting
Tests that previously chose to use `nu-command` for their scope will
still use `nu-cmd-lang` + `nu-command` (command list in the granularity
at the time)

crates/nu-command/src/lib.rs

@@ -13,6 +13,7 @@ mod filters;
 mod formats;
 mod generators;
 mod hash;
+mod help;
 pub mod hook;
 mod input_handler;
 mod math;
@@ -45,6 +46,7 @@ pub use filters::*;
 pub use formats::*;
 pub use generators::*;
 pub use hash::*;
+pub use help::*;
 pub use hook::*;
 pub use math::*;
 pub use misc::*;