port painting to qml & add list view

this brings more of the UI into the qml world, this time the rendering
of the filelight map. it is implemented using qtquick shapes of stacking
circles. this also introduces a listview to more reasonably glance,
navigate and manage files inside the current scope (as opposed to the
previous labeling approach inside the map). to ease discoverability the
hover states between map and list are somewhat linked so it becomes
easier to spot which segment is where in the list, and vice versa.

to facilitate all this a huge amount of reshuffling happened:

- item.cpp no longer exists, its functionality moved into either qml or
the map.cpp
- new classes dropperitem (to receive drop events from qml)
contextmenucontext (to implement the c++ side of context menu actions)
filemodel (to model the file objects for the listview)
- File is no longer a QObject, this has been moved up one level in the
architecutre -> Segment now is a QObject and delegates most of the UI
relevant functions from File
- Files are now "linked" to their segment through a uuid string. this
allows the UI code to establish a relationship between entities in the
listview and the mapview. this is intentionally not pointer based to
avoid clashes, confusion, and to prevent the Files from contributing to
the lifetime of Segments (and thus complicate the entire shebang)
- various settings have been retired as they are no longer applicable:
AA is now always on, there is no practical reason why the user would
disable it in 2022, font size (now following system defaults and
sometimes able to scale down if not enough space)

BUG: 461193
BUG: 458181
BUG: 444057
BUG: 434146