Either remove sync permissions or implement sync features

[CampelloManuel]

As of version 7.1.9, the app requires system permissions for sync, which are not used. Possible solutions

1. remove ALL sync code and features and don't request the permissions
2. implement some sync features (like the calendar ? or other note apps ? or google account ?) that actually use those permissions

I think I'm going to remove sync functionality and permissions, since it would improve the privacy of the app