Add --no-git option

[Aehmlo]

Some unnecessary exposition about my use case

While updating my home-manager configuration recently, I discovered that exa now has a program module available, with the option programs.exa.git to alias exa to exa --git. I happily enabled this option but quickly found myself in situations where I didn't want the git status to shown. While I could use something like $(which exa) -l, I far prefer the ergonomics of a --no-git option (and it plays more nicely with other tools to boot).

This PR adds the --no-git option. This option overrides --git in all cases and disables showing the Git status of files in long view (-l). This enables users of shell aliases and the like to turn off git status display in an ad hoc manner

Somewhat tangentially related: #1044.

(This is my first contribution to this codebase; I've done my best to make all the appropriate changes, but I'd appreciate any pointers if there's something I've missed. I took inspiration from the --no-icons option as prior art.)

[cafkafk]

Hey, fyi, exa is super dead, but if you'd like to, consider submitting this pr to eza.

[Aehmlo]

@cafkafk Thanks for the head-up. I just created eza-community/eza#168.

[ariasuni]

Closing this since exa is unmaintained (see #1243), and this PR has been merged in the active fork eza.