mso_sta_epg_subnet: Manage EPG subnets in templates (#51278)

A new module to manage EPG subnets in MSO schema templates.

lib/ansible/module_utils/network/aci/mso.py

@@ -99,7 +99,7 @@ def mso_subnet_spec():
     return dict(
         ip=dict(type='str', required=True),
         description=dict(type='str'),
-        scope=dict(type='str'),
+        scope=dict(type='str', choices=['private', 'public']),
         shared=dict(type='bool'),
         no_default_gateway=dict(type='bool'),
     )