feat: users service for all kinds of user management

[PiquelChips]

Summary of the PR

Add a user service to eventually replace the profile service. Also a lot of refactoring of auth service

Steps before PR review

• Create user if it doesn't exist in auth callback handler
• Finish writing specification
• Implement new user handlers
• Make sure username is unique in username validation
• Use regex for username validation
• Implement the feature
• Test the feature
• Make sure all checks pass
• Properly document the feature in the PR and docs

Changes

• Add public configuration that will be publicly exposed
  • Involved moving policy types to config package
• Deprecated policy endpoint in auth handler
• Replace with config.json handler which serves the public config
• Add new user handler (adds user deletion and listing)
• Add new user update admin system that allows updating role and email of a user
• Add security to openAPI spec base
• Add proper username validation
• Huge refactor of auth service. Simplifes interface and integrates better with user service