feat: promote to moderator instead of transferring moderator role

[dostulataa]

Allow multiple moderators for a room

Please read the CONTRIBUTING.md before opening a PR.

Issue: #195

Description

Descriptive pull request text, answering:

• What problem/issue are you fixing? every user can be a moderator at the same time
• What does this PR implement and how? promoting a user to moderator does not remove the promoter's moderator role

[dostulataa]

This still has a bug and stays a draft until fixed.