feat: Add Google Drive storage backend with custom endpoint support (#613)

* feat: Add Google Drive storage backend with custom endpoint support

- Implement Google Drive storage backend using service account authentication
- Add support for custom Google Drive API endpoints for testing
- Include comprehensive test setup with mock services
- Add configuration options for Google Drive credentials and folder ID
- Update documentation with Google Drive configuration examples

* remove debug messages

* Improve tests

* Add mounting tip on documentation

* Replace deprecated lib usage

* Fix identation

* Fix googledrive tests

* Fix googledrive support for _FILE credentials

* Remove googledrive test unecessary echos

test/googledrive/oauth2_config.json

@@ -0,0 +1,37 @@
+{
+   "interactiveLogin": true,
+   "httpServer": "NettyWrapper",
+   "tokenCallbacks": [
+       {
+           "issuerId": "issuer1",
+           "tokenExpiry": 120,
+           "requestMappings": [
+               {
+                   "requestParam": "scope",
+                   "match": "scope1",
+                   "claims": {
+                       "sub": "subByScope",
+                       "aud": [
+                           "audByScope"
+                       ]
+                   }
+               }
+           ]
+       },
+       {
+           "issuerId": "issuer2",
+           "requestMappings": [
+               {
+                   "requestParam": "someparam",
+                   "match": "somevalue",
+                   "claims": {
+                       "sub": "subBySomeParam",
+                       "aud": [
+                           "audBySomeParam"
+                       ]
+                   }
+               }
+           ]
+       }
+   ]
+}