Adding auth/gcp.Authenticator, rearranged server/kit.Server's logging stack

[auth/gcp] Adding basic google web auth flow capabilities (#231)

* initial WIP

* removing IAM verifier, cleaning up verify logic

* docs

* hooking in custom exception func

* renaming file

* removing unneeded client

* ensuring cookie is cleared

* cleaning up var declarations

* fixing the logger

* Forbids instead of redirecting

* cleaned up verify logic

* state cleanup

* simplifying logic

* avoiding a verify of an empty token

* adding some initial authenticator tests, callback still needs coverage

* adding some callback tests

* making notes in README