feat: add team label reusable workflow

[itsyoboieltr]

Instead of copy-pasting the implementation of add-team-label to other repositories, such as metamask-extension and metamask-mobile, it should be possible to call the workflow directly from the github-tools repository, if we make it a reusable workflow. This is great, because if we make a change to the workflow in the github-tools repository, the changes propagate to other repositories as well.

More information about reusable workflows: https://docs.github.com/en/actions/using-workflows/reusing-workflows

This kind of aligns with MetaMask/metamask-extension#25509, but not exactly. The shared library would still be needed nevertheless, as this is only sharing the workflow definition, but not the scripts that are run during the workflow. The scripts still need to exist in all the repositories (for now). Ideally, we would make the shared library an npm package that can be installed in the different repositories to allow for the sharing of scripts.

Resolves: https://github.com/MetaMask/MetaMask-planning/issues/2760

[legobeat]

This kind of aligns with MetaMask/metamask-extension#25509, but not exactly. The shared library would still be needed nevertheless, as this is only sharing the workflow definition, but not the scripts that are run during the workflow. The scripts still need to exist in all the repositories (for now).

Why is this?

Ideally, we would make the shared library an npm package that can be installed in the different repositories to allow for the sharing of scripts.

Can we not simply inline the script into this repo?

• add-team-label workflow is missing implementation #24

[itsyoboieltr]

We can! and now that we have this public repository for scripts like this, we should, as it is a much better solution 😄 @legobeat