Set JWT_KEY as private key option

[stoopidJSON]

User Story

As a developer
I'd like to be ablet to set the JWT_KEY to a private key
So that I can generate even more secure JWT's.

Acceptance Criteria

• Code that allows for either a string or a private key to be used as the JWT_KEY
• PR merged to master with the above change

Notes

Can probably add proper JWT auth tests with this ticket.

[stoopidJSON]

The existing code facilitates this. JWT key is a function of infra. This ticket can be closed.