fix: remove azurerm provider declaration

this fixes an issue where an explicitly configured provider in a parent
configuration is not properly obeyed. In this particular case it can lead
to the module executing with azure cli authentication instead of e.g. an
explicitly configured azure service principal.

https://www.terraform.io/language/modules/develop/providers
> A module intended to be called by one or more other modules must not contain
> any provider blocks.

Author: JohannesRudolph

main.tf

@@ -11,11 +11,7 @@ terraform {
     }
   }
 }
-
-provider "azurerm" {
-  features {}
-}
-
+ 
 data "azurerm_management_group" "root" {
   name = var.mgmt_group_name
 }