cloudconnector: fix of cloud applications
- Adds possibility to connect through Google or Dropbox accounts and manage stored files. (PR #1920)
- Uploads a file to a cloud application.
- Uses refresh_token to get a new token when the token is expired.
- TODO Add SQLAlchemy signal 'after_insert'.
- Improves PEP257 and PEP8 code styles.
Co-authored-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Signed-off-by: Eirini Psallida <eirini.psallida@cern.ch>