Consider porting nymphcast-player to QML about nymphcast

[MayaPosch]

I have reduced the minimum sizes for the Player window, which should at least help with making it fit better on smaller screens. Minimum width is now 360 px, which assuming 2x scaling on the 720p display on the PinePhone should make it fit properly.

As for making the Player UI work better across resolutions, this is something that definitely needs looking at. There are ways to make the current layout into a flow layout: https://doc.qt.io/qt-5/qtwidgets-layouts-flowlayout-example.html

Styling the standard widgets using stylesheets will also allow for them to fit better on a specific platform. https://doc.qt.io/Qt-5/stylesheet-syntax.html

[MayaPosch]

Stylesheet support is now available in the Player. By default default.css in the binary folder will be used. I have pushed a simple stylesheet for now that changes the color of the window and changes the size of the tabs.

The location of the stylesheet file is set in the registry (on Windows) or its equivalent (per the Qt documentation). The idea is to have different stylesheets for different target platforms that can style the GUI for that platform.