Add support for self signed certs for git in the MLOps pipeline

RHOAI now requires that all components and features support the use of self signed certificates that would be enabled in all cluster environments. This story was created as a follow up to https://issues.redhat.com/browse/RHOAIENG-171

A spike was completed on this issue link here. A way to test if the pipeline is running successfully with the self signed certs would be to clone from a git repo that is in the Redhat private network.

Acceptance criteria:

• A self signed cert can be passed as a parameter to the MLops pipeline and can be used for use with private services throughout the pipeline, but for ones that only use git
• Document this process and an optional step in the pipeline docs