feat: allow to configure networkWatcher RG tags

[wetwicky]

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Description

Is your feature request related to an issue?

Cannot use the module resourcegroup_networkwatcherrg as it doesn't allow to customize the tags which for some organization using azure policies to inherit tag from subscription cause terraform to detect drift every time terraform is triggered.

# Resource groups module for network watcher
module "resourcegroup_networkwatcherrg" {
  source              = "./modules/resourcegroup"
  count               = var.network_watcher_resource_group_enabled ? 1 : 0
  subscription_id     = local.subscription_id
  location            = var.location
  resource_group_name = "NetworkWatcherRG"
  tags                = {}
}.

adding an optional input variable to configure the tag would alllow to use it

Describe the solution you'd like

add an input variable to be able to setup tags on NetworkWatcherRG resource group.

# Resource groups module for network watcher
module "resourcegroup_networkwatcherrg" {
  source              = "./modules/resourcegroup"
  count               = var.network_watcher_resource_group_enabled ? 1 : 0
  subscription_id     = local.subscription_id
  location            = var.location
  resource_group_name = "NetworkWatcherRG"
  tags                = var.network_watcher_resource_group_enabled 
}