Do not release moduletemplate.yaml file

[kwiatekus]

Description

Do not release moduletemplate.yaml file

• Do not generate moduletemplate as part of keda release flow
• Move asset generating script execution from prow to GH actions (it should not be building module image ad uploading anything to artefact registry) (this step should be done also in serverless-manager)
• Remove dependency in out integration tests to downloaded module template asset
• Use the release.sh as asset verification before publishing release (Asset verification for GH Actions Release Workflow serverless#458)

Reason
Module-template is an internal mechanism and it must be generated by the submission pipeline only. The module template must be removed from OS projects.