* Bumped compat to 10
* Removed --parallel from rules, standard in compat 10
* Bumped minimum version debhelper (>= 10)
* Added build dependency liblxqt-dev (>= 0.11.0)
* Followed Multiarch hinter suggestions
- qtermwidget5-data marked as Multi-Arch: foreign
- libqtermwidget5-0 marked as Multi-Arch: same
- libqtermwidget5-0-dev marked as Multi-Arch: same
* Simplified optional symbols