different github locations should be able to co-exist in the same namespace pipelines

**Is your feature request related to a problem? Please describe.**
If I add a pipeline from github.ibm.com (private) and another pipeline from github.com (personal) in the same namespace, they will try to share the same git-credentials key. This will fall either pipeline depending on which set of creds are correct during the run of either pipeline. I should be able to run multiple different github contexts inside the same namespace. Or, explicitly let people know that you can't do this

**Which persona(s) does this feature benefit (e.g. developer, SRE, etc)?**
dev/sre

**What is the impact of not having this feature? What will be the benefit of having this feature?**
not having this feature creates an unecessary barrier to usage. Multiple secrets for multiple githubs should be possible. The benefit is better rate of adoption due to higher flexibility of the solution

**Describe the solution you'd like**
allow pipelines to use a git-cred per pipeline or per github instance. Maximum flexibility would be per pipeline I think. This allows multiple user PATs to be used in the case of a joint solution with many different ISVs or customers or developers... etc.

**Describe alternatives you've considered**
alternative is to warn and prevent this. check for different github existence and prevent addition of different gitub creds in a namespace.

**Additional context**
Add any other context or screenshots about the feature request here.