Adds https mode to credentialConfig

[juliusl]

What this PR does / why we need it:
Similar to the current http credentialConfig mode, this PR adds a https mode with additional options for enabling full mTLS with a local auth server.

This enables hardening localhost connections in environments that may allow merged network namespaces w/ running containers.

Tested integration manually w/ private build of AKS/ACR artifact streaming.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Please check the following list:

• Does the affected code have corresponding tests, e.g. unit test, E2E test?
• Does this change require a documentation update?
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have an appropriate license header?