widget apps: Prepare for refactor

This is mostly moving from QVariantHash to QVariantMap to take advantage of the automatic type conversions with CPP<=>QML as the apps migrate from QWidgets to QML.

configure-printer: a minor cmakelists change for tooling

Also, a few warning fixes and folded in print-manager/!20 (closed).

See commits for each app for more detail.

re: #2 (closed), #4 (closed), #6 (closed)