Implement JWT & Rework security

[ZakShearman]

This PR moves the authentication from Spring's form based auth to JWT authentication.

This has the benefits of a more common standard as well as including

To-do:

• Implement JWT fully
• Re-work roles
• Re-do security config
• Implement CSRF protection

Auth workflow:

• Post request to /auth/login with a body containing values username and password
• Cookie on the client is set

Added dependencies:

• jjwt-api
• jjwt-impl
• jjwt-jackson