Add crowdin action

[anbraten]

With crowdin/crowdin-cli#776 and crowdin/crowdin-cli#794 deleting obsolete files which got removed in the source language (en) works now using the cli which is used by this github action. Therefore this PR introduces the Crowdin action to replace the old integration.

Steps needed before merging

• disable the integration in crowdin
• generate an api token in crowdin and save it as secret CROWDIN_PERSONAL_TOKEN in github

[anbraten]

@MilosKozak Afaik as you are the repo and crowdin project owner, you would need to support us with the secrets. (hope this is correct and sorry for pinging)

CC @peterleimbach

[MilosKozak]

I can do it. Just tell me what you need

[anbraten]

1. Disable the github integration in crowdin: https://crowdin.com/project/androidapsdocs/integrations/system/github
   Should be enough if you click "pause sync"
2. Create a new crowdin api key: https://crowdin.com/settings#api-key and save it in github https://github.com/anbraten/repro-crowdin-delete-obsolete/settings/secrets/actions as secret: CROWDIN_PERSONAL_TOKEN

Thanks

[peterleimbach]

@Milos: Could you implement @anbraten requirements for the actions in Github? Can merge this PR?