Suggest exemption removal when all resources covered by exemption are compliant

[gregslack78]

This feature request is based on a new policy feature for exemption substates.

https://techcommunity.microsoft.com/blog/azuregovernanceandmanagementblog/introducing-compliance-substate-for-azure-policy-exemptions/4541703

Now that exempt resources are being evaluated and reported on in a what-if manner, we should be able to check if all resources affected by a specific exemption are compliant and suggest the removal of the exemption in the plan output

[anwather]

I'm ok with this as optional output, I'd also like to include the compliance substate in the non-compliance reporting as well.