Create KDE integration package
Enable native Qt5 file dialogs on Solus Plasma by creating the libreoffice-common-kde-integration package.
I did not enable full Qt5 support because it doesn't play nicely with dark themes (e.g. Breeze Dark).
Browsed in menus and saved a file, setting a password via file dialog.
LibreOffice works correctly even if libreoffice-common-kde-integration is not installed; it correctly falls back to GTK3.
Reviewers: Triage Team, JoshStrobl
Reviewed By: Triage Team, JoshStrobl
Subscribers: Girtablulu, JoshStrobl
Differential Revision: https://dev.getsol.us/D6487