`Development`: Define Github workflow to automatically assign the database team

[Mtze]

Automatically request a review of the DB Maintainer Team if a PR contains a DB migration

Checklist

General

• [ ] I tested all changes and their related features with all corresponding user types on a test server.
• [x] This is a small issue that I tested locally and was confirmed by another developer on a test server.
• [ ] Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• [x] I chose a title conforming to the naming conventions for pull requests.

Motivation and Context

Database changes have to be reviewed carefully and reviewed with the complete database context in mind. The DB Maintainer sub team will take care of DB migration reviews.

This PR automatically requests a review from the DB team if a PR has the database label.

Review Progress

Code Review

• [ ] Review 1
• [ ] Review 2