CI: Add obs-crowdin-sync

[Vainock]

Description

Adds the obs-crowdin-sync GitHub Action to enable automatic upload of English language files to Crowdin. CROWDIN_SYNC_CROWDIN_PAT was already added as an organization secret.

Motivation and Context

Automation is great.

How Has This Been Tested?

In a fork.

Types of changes

Checklist:

• [x] I have read the Contributing Guidelines.
• [x] All commit messages are properly formatted and commits squashed where appropriate.
• [x] My code is not on master or a release/* branch.
• [x] The code has been tested.
• [x] I have included updates to all appropriate documentation.