Clean up the repo a bit, and add some unit tests

• Add a bunch of unit tests for different workflows
• Rework the different util modules and merge them where relevant
• Resolve some TODO items in config.py (netmasks are now validated)
• Add some :term: directives to docstrings
• Resolve a pytest warning about an unregistered mark @pytest.mask.workflow

gso/workflows/router/terminate_router.py

@@ -57,6 +57,8 @@ def deprovision_lt_ips(subscription: Router) -> dict:
 
 @step("Remove configuration from router")
 def remove_config_from_router() -> None:
+    #  FIXME: Add actual content
+    #  TODO: update unit test accordingly
     pass