This PR just tidies up some tests by removing unused code:
1. If the filesystem is not touched, don't use the filesystem
playground/sandbox
2. If the filesystem is not touched, don't specify the `cwd`
3. If the command is short, don't bother wrapping it in `pipeline()`
4. If the command doesn't have quotes, don't bother with a `r#"..."#`
raw string
Part of #8670.
* move commands, futures.rs, script.rs, utils
* move over maybe_print_errors
* add nu_command crate references to nu_cli
* in commands.rs open up to pub mod from pub(crate)
* nu-cli, nu-command, and nu tests are now passing
* cargo fmt
* clean up nu-cli/src/prelude.rs
* code cleanup
* for some reason lex.rs was not formatted, may be causing my error
* remove mod completion from lib.rs which was not being used along with quickcheck macros
* add in allow unused imports
* comment out one failing external test; comment out one failing internal test
* revert commenting out failing tests; something else might be going on; someone with a windows machine should check and see what is going on with these failing windows tests
* Update Cargo.toml
Extend the optional features to nu-command
Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>