Facettiertes Filtern im Backpack, oben Button Leiste, konfigurierte Kategorien, die vom Server kommen

[wolfspelz]

Tasks:

• Filter definitions in WebEx based on properties (mostly based on having an aspect)
  • [x] Config classes for filter definitions
  • [x] Filter definitions in ConfigController
  • [x] Texts
  • [x] Images
• Filter application in client BackpackWindow
  • [x] Parsing config into filter objects
  • [x] Filter functionality in BackpackWindow
  • [x] Button bar below title bar
  • [x] Filter icons in buttons
  • [x] Resolve button icon URLs into data URLs via background
  • [x] Styling
  • [x] Only show filters that match at least one item and hide filter bar when less than two filters would be visible