Upload coverage blob to azure and send download url to bx automation

• Change the image to the standardized automation image which includes azure cli tools
• add new stage so that we are guaranteed to run after unit tests run
• generate a tarball of the coverage directory which should be created when unit tests run
• generate a download url for said tarball and send it to bx-automation so it can be downloaded by child pipeline jobs
• added link in gitlab-ci-main as we want to use this in a branch first