Add OIDC Auth to EPR

[ninjamast3r]

Planning to add OIDC support to EPR by way of Keycloak. The goal is to require authentication on most endpoints. This is a stepping stone to implementing RBAC.

Stuff we need:

• Doc on spinning up Keycloak and getting it configured (or a script).
• Figure out the auth flow for a user interacting with EPR. Getting them a raw JWT is good enough for the first pass.
• Add Keycloak to the deployment with the other prereqs.
• Add some EPR middleware to validate access tokens.

May need to split these into multiple tickets.