feat: authentication middleware for the GoCert server

[kayra1]

Description

This PR implements the authentication and permission functionality described in TE091. The /metrics and /status endpoints are left unauthenticated, as well as the first POST request to the api/v1/accounts endpoint. For more details, please read TE091.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that validate the behaviour of the software
• I validated that new and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[saltiyazan]

Looks good, I ran into one issue while testing that I commented