Tags from RG and input tags

[alambike]

Motivation

Currently we have different ways of set the tags in the azure resources defined by the azure-* modules:

tags

azure-resource-group => tags comes from input
azure-sa => tags comes from input
azure-aks => tags comes from input
azure-vmss => tags comes from input (vars.commont.tags)
azure-vnet-and-subnet => tags comes from input (var.tags)
azure-public-prefix => tags comes from input (var.tags)
azure-nsg-nsr => tags comes from input
azure-flexible-server-postgres => tags comes from input

azure-disk => tags have an ignore_changes (It's supposed to come through the Azure police)
azure-app-gateway => tags have an ignore_changes (It's supposed to come through the Azure police)

azure-mi => tags comes for input OR from RG setting the tags_from_rg flag to true
azure-kv => tags comes from RG setting the tags_from_rg flag to true

Acceptance criteria

We want to:

• Extend the usage of the tags_from_rg flag, to all azure modules
• Allow definition of custom tags using a map input, like vars.tags, default to {}
• If both options are defined (tags_from_rg + var.tags) a merge of both maps should be applied, with major precedence to the var.tags input (if same tag is defined in the RG and var.tags, `var.tags wins)