feat: support for git submodules

Needed for the llrfctrl server configs for external facilities (they use the DESY/DOOCS config as a submodule)

ConfigGenerator/ExternalTools/Git.py

@@ -79,7 +79,7 @@ class Repository:
         :param reset_changes: Whether to discard local modifications (reset --hard)
         """
         if not os.path.exists(self.repository_folder):
-            self.clone()
+            self.clone('--recursive')
         else:
             if not self._is_git_repository():
                 raise NotARepositoryError()
@@ -92,7 +92,7 @@ class Repository:
                     sanitizer = r"^[ .]|[/<>:\"\\|?*]+|[ .]$"
 
                     os.rename(self.repository_folder, self.repository_folder + '_' + re.sub(sanitizer, '_', current_pull_url))
-                    self.clone()
+                    self.clone('--recursive')
 
                     return
 
@@ -124,6 +124,7 @@ class Repository:
                         'period. As a work-around, please delete the repository'.format(
                             self.name))
                 raise OperationFailedError()
+            result = self._git('submodule','update','--recursive')
 
     def get_remote_url(self, remote: str = 'origin') -> str:
         log.debug(f"Checking url of {remote}...")
@@ -193,4 +194,3 @@ class Repository:
         :param msg: additional argument to be passed to git arg
         """
         self._git('commit', "-m", msg)
-