AlbumHeader: Fix appearance
This merge request fixes the status bar & navigation bar of the album view when the view is loaded:
- The correct theme is applied to the status bar to make it readable no matter the color theme and the position in the view.
- The navigation bar's color is also updated when the view is loaded taking into account the position in the view.
This merge request also brings cosmetic changes to:
- The AlbumHeaderFlowLayout that is moved into a separate file
- The UINavigationController extension that is now separated from the MediaCategoryViewController implementation and is now located in the Extensions' folder.
Closes #1481 (closed)
Closes #1489 (closed)