Add option to directly add all contributors with reason "code"

[Andre601]

Is your feature request related to a problem? Please describe.
No issue

Describe the solution you'd like
It would be cool to have an option to let the all-contributors bot add all people that contributed to the repository with PRs (Have the "contributors" label next to their name in issues/PRs and are shown in the contributors page).

The command could be something like @all-contributors please add all contributors and the bot would make a PR containing everyone listed in the contributors tab.

Describe alternatives you've considered
The only alternative would be to manually add them one by one, which not only is slow, but also can cause conflicts when multiple PRs are made at the same time without merging others first (see #310 for context)

Additional context

[Berkmann18]

This would be cool indeed, there's a complementary feature (still a WIP) on the CLI which would enable it (and by extension the bot as well which some additional changes) to automatically add contributors.
Feel free to contribute/help if you want.

[samajammin]

Came here to suggest this feature! Would be great if there was an ability to backfill all project contributors without having to do it manually one by one. Awesome project overall!

[Berkmann18]

@samajammin That's what all-contributors/cli#196 is aiming to solve but as I've mentioned across the board, I didn't manage to fix some blocking issues (and I haven't had the time to look into it lately).
If you want to help, then please do.

[Andre601]

I close this issue as it already exists as PR (See above comment) and to move to the actual right repository for this stuff...