Add Microsoft.AVS.Migrate module with Deploy-MigrateApplianceVM cmdlet

[neharanideswal]

Introduces a new public Run Command cmdlet, Deploy-MigrateApplianceVM, to deploy the Azure Migrate appliance VM from its OVA template into an AVS SDDC.

This PR closes #

The changes in this PR are as follows:

1. Creates a Module for Microsoft.AVS.Migrate
2. Create the Run command cmdlets for the deployment of the migrate appliance

I have read the contributor guidelines and have completed the following:

• Formatted the code using VSCode default formatter for PowerShell.
• Tested the code end-to-end against an SDDC.
• Documented the functions using standard PowerShell markup and applied AVSAttribute to newly exported functions.