seafile-seahub: Update to 7.1.2, refresh patches

seafile-seahub: Update to 7.1.2, refresh patches

Other changes include:

* Package Python bytecode in seafile-seahub, add source code package
  (seafile-seahub-src)

* Instead of changing default settings, custom settings will be added to
  /etc/seafile/conf/seahub_settings.py during seafile-server setup

* Use SEAFILE_UCI_DATA_DIR, which will be added to seafile-server

* Clean up Makefile formatting

* Add myself as a maintainer

Signed-off-by: Jeffery To <redacted>