Add the possibility to specify tags for the staging ressource group.

[dana23746]

Hello !

In most of the cases, companies use azure policies to require tags on resource group during the creation.
In this document https://github.com/Azure/azvmimagebuilder/tree/main/solutions/2_Adding_Tags_to_Staging_Resource_Group you provide only this capability after the creation. It would be nice to add the feature to specify tags.

Another alternative would be to allow peoples to choose an existing resource group as the staging one.

Best regards.