port to qtquick

• the UI is now written using qtquick. it's largely a replication of the widget UI with some simplifications to closer resemble the simplicity of the original codeine player design. offering a hopefully more streamlined UX we can iterate on
• now using qtmultimedia instead of phonon. with the advance of the ffmpeg backend qtmultimedia should work more reliably and we decided to deprecate phonon anyway. while I had a libvlc based prototype for a while it ultimately didn't amount to anything because the release cadence of libvlc is too slow for us
• mpris support has been adjusted accordingly
• audio player support has been removed. it always felt awkward and I suspect it wasn't really used
• as part of this the analyzer code base is no more
• dvd support has been removed. I have no hardware and it was broken for a while already without anyone fixing it
• load view has been removed to simplify the UI and UX. seeing as without disc support we only ever open urls the view wasn't too useful anymore but had a lot of code and special handling. this effectively means that the new page stack only needs to deal with one page (well, and the about page, but that doesn't really count since that always sits on top)