It's hard to debug two processes running in the same pod. We need to
decouple the two processes into two services.
### Changes 🏗️
Move DatabaseManager away from RestAPI as a standalone serice
### Checklist 📋
#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
<!-- Put your test plan here: -->
- [x] Manual test