Clang warns on `OnTouchEvent()` function, which is overridden, but is
missing the `override` keyword

```
In file included from InfiniTime/src/displayapp/screens/Music.cpp:18:
InfiniTime/src/displayapp/screens/Music.h:43:14: warning: 'OnTouchEvent' overrides a member function but is not marked 'override' [-Winconsistent-missing-override]
        bool OnTouchEvent(TouchEvents event);
             ^
```

In the first `Music::Refresh` call the lastLength and totalLength are
not initialized. The `lastLength` value is read first from the
musicService. Naturally in the first itereation that is changed and
`UpdateLength()` is called. There the variable `totalLength` is used as
well, but that variable isn't initialed to a sensible value yet. This
leads to sometimes the `Music.h` screen segfaulting (depending on the
random uninitialized data in the `lastLength` variable)

Don't use relative imports like `../foo.h` as those depend on the
relative position of both files. Rather than that use imports relative
to the `src` directory, which explicitly is part of the include
directories.

Fix music app

 - Enable LVGL animation (and disable groups, which were not used), and set the speed.
 - Fix disc animation and progress display by initializing lastIncrement at 0 (a random value will be used otherwise, in release build)