Add Usermanagement

[weristspokey]

• [x] Create User Entity for storing in the database via php bin/console generate:doctrine:entity
  • [x] create corresponding table in database via php bin/console doctrine:schema:update
• [x] Login as Admin
• [x] Register as new User
  • [x] register Form via php bin/console doctrine:generate:form AppBundle:User
• [x] Login as User
  • [x] Login Form
• [x] Logout
• [x] bcrypt for security

[weristspokey]

• [ ] Exceptions for entering already used values