debian/control: adopt some packaging from Debian where appropriate
- Update Section, some B-Ds, Ds.
- Remove obsolete Conflicts, Breaks, Repalces, Pre-Depends.
- Update Description.
- Rename library package to match Debian.
- liblomirisystemsettingsprivate0{ => .0}
- Add Breaks, Replaces, Provides on the old package name.