[Module Proposal]: `avm/ptn/maintenance/azure-update-manager`

### Check for previous/existing GitHub issues/module proposals

- [X] I have checked for previous/existing GitHub issues/module proposals.

### Check this module doesn't already exist in the module indexes

- [X] I have checked for that this module doesn't already exist in the module indexes.

### Bicep or Terraform?

Bicep

### Module Classification?

Pattern Module

### Module Name

avm/ptn/maintenance/azure-update-manager

### Module Details

I would like to have a Pattern Module for Azure Update Manager which creates multiple Maintenance Windows to provide multiple Update Rings. The Maintenance Windows should use a Dynamic Scope in Combination of a Tag. In this Module it should also include also the needed Azure Policies to deploy the needed Policy for AUM and for the Tag Deployment to make sure that every Azure VM and Azure Arc Enabled Server has the specific Tag defined as Required. This make sure that every server will be part of a Maintenance Window in AUM. For the Azure Policy it will also create managed Identity.

### Do you want to be the owner of this module?

No

### Module Owner's GitHub Username (handle)

akhilthomas011

### (Optional) Secondary Module Owner's GitHub Username (handle)

_No response_