Port preferences to HdyPreferencesWindow

Merged Krifa75 requested to merge Krifa75/totem:totem-preferences-window into master


So this is the port to HdyPreferencesWindow. Please do not hesitate to give some kicks if there is mistakes.
There is only one thing I'm struggling with, is that the GtkScales I can't make them homogeneous. I used GtkSizeGroup but no changes...


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