Create comprehensive e2e test environment for different auth and communication protocols

[adamtagscherer]

Currently we have tests for mTLS in the root's Taskfile.yaml, that will be enabled in #483.

The purpose of this issue is to move the mTLS testing environment from the root's Taskfile to e2e/Taskfile.yaml a newly separated Taskfile just for this purpose, becase the one in the root has ~1500LoC and is hard to manage by now. Besides this we can revamp the mTLS test case - task test:spire - and also add a new test case for the JWT auth.