Add skip variable for remove test resources to support debugging

[benbp]

In case people want to leave their resources around for debugging after test failures.

The naming format was chosen to be consistent with our other user-facing Skip variables used in the release pipelines (e.g. here).

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[heaths]

Looks fine, but how are they expected to set this? I assume through a manual pipeline run and then set the variable? Should we document that somewhere?

[benbp]

Looks fine, but how are they expected to set this? I assume through a manual pipeline run and then set the variable? Should we document that somewhere?

Yes, exactly. I was going to update our wiki documentation after merge since that's where I think most of the docs around the live test pipeline lives.

[ghost]

Hello @azure-sdk!

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[benbp]

@heaths docs added here.