Adding inject hld update pipeline script

[bnookala]

• Adds a script that injects a hld update stage into any existing azure pipelines yaml
• This pipeline yaml is not guaranteed to be correct - it may still need modifications to make work with any pre-existing pipelines.
• Resolves https://github.com/microsoft/bedrock/issues/1362

[mtarng]

Is this a completely standalone command? Should we add official documentation for this?

Do we also need to inject environment variables to be consumed by build.sh scripts?