feat(IAM Policy Management): Updated role template references changes and test cases

[bbellamgari]

PR summary

This PR includes changes for role_template_references changes for policy template creation.

PR Checklist

Please make sure that your PR fulfills the following requirements:

• The commit message follows the Angular Commit Message Guidelines.
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Current vs new behavior

Currently we do not support role_template_references in policy templates. With this new behaviour, we are adding that functionality

Does this PR introduce a breaking change?

• Yes
• No

Other information

https://github.ibm.com/IAM/AM-issues/issues/4045

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}