- Create method to check if email is empty or the default AuthMe email (avoids repetition)
- Check that input email has '@' inside text (relates to #1105)
- Introduce Usage.DEPRECATED to mark the hash algorithms accordingly
- Log warning when such a deprecated hash algorithm is used
- Update hash algorithms doc page
- Separate provider methods from other tasks performed on startup
- No longer requires BukkitService to be instantiated manually
- Merge MetricsManager and Initializer into OnStartUpTasks