**What**
- add accept invite endpoint
**Invite accept flow**
- authenticate using the auth endpoint to create and auth-user
- invoke accept endpoint with token and info to create user
**What**
- remove auth provider entity
**Why**
- The auth provider entity was not really used anywhere
**How**
- Keeping loader behavior as is but removing the
Co-authored-by: Sebastian Rindom <7554214+srindom@users.noreply.github.com>