Implement security

[mariuszluciow]

• Support for OAuth2
• Custom user database
• Each user should have his own namesapce
• Creating access keys
• Support for LDAP (nice to have)

[mariuszluciow]

Worked around https://github.com/spring-projects/spring-boot/issues/5093 problem in #160 Todos left:

• Basic Auth
• [ ] Store users in database
• [ ] Autogenerate admin account if users count == 0
• SSO
• [ ] First logged in user should be promoted to Admin
• [ ] Create User data for each user that logs in
• Internal
• [ ] Dedicated table with worker type users
• [ ] Generation of worker creadentials during startup (maybe bootstrap script in docs)
• General
• [ ] Implement namespaces along with concept of owner and member
• [ ] Admin panel with user management
• [ ] Docs