* ci: Add mock build alternative for fast testing

* ci: Always cache build

* ci: Extract steps to download build stage artifacts

* ci: Add template to release to GitHub

* ci: Add template to release to Azure Universal Artifacts

* ci: Split mainline to two pipelines

Identified a bug in the script which uses the azure image when attempting to upgrade python3-pip.
Package index was out of date because apt-get update was not ran before attempting the upgrade.

Fix README change mistake

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