Add OpenID Connect (OIDC) Authentication Support

[austince]

Will have to periodically fetch a token from a specified authentication provider to hook into the Ververica Platform's authentication. Will likely involve adding a/ refactoring the auth_store in /controllers/appmanager to create authenticated contexts from a token fetched from OIDC, as well as adding CLI flags/ env variables for those credentials.

May not be possible to tie OIDC to Vp API Tokens 1:1. Although might be possible if we created namespaces with only the user instead of system:authenticated?

This is a necessary requirement for working interoperably with the suggested production setup from Ververica.