[FEATURE] Add support for roleDefinitions functions

[mattjvan]

Your suggestion

The roleDefinitions function has been added to Bicep, and would be good to have support by PSRule.

Alternatives

n/a

Additional context

ERROR: InvalidTemplate - Deployment template validation failed: 'The template resource ... is not valid: The template function 'roleDefinitions' is not valid. Please see https://aka.ms/arm-functions for usage details.

[github-actions]

Thanks for raising your first issue, the team appreciates the time you have taken 😉

[mahindramvadala]

We are facing the same issue in our organization. Looking forward to have the roleDefinitions function included.