optimized mobile menu controller

added _getCategoryComponent directly as param - save as var not necessary anymore
deleted _getCategoryComponents function and splitted _getChildPages into 2 separate functions

moved _getCategoryComponents code into _getChildPages and created new function _getChildPagesRecursive
for the recursive calls to find child pages
breakpoint in Gallery as setting, write all css code in scss, use variables in scss
Implement substract and add for kwf_model_abstract
Check if mimeType is set before checking value
fix assetVariables with uppercase letters in scss files

sass lowercases everything so the variables wheren't found anymore
add cache folder
Merge remote-tracking branch 'github/master'
Change styling for image upload
Improve styling for long file name
Add show information on hover
Show error message in image-upload component
Change grey region of crop-image to red if too small
Add translation
Remove background-color to show loading image
Fix bug when switching between user-define dimensions
Save user selected crop region for recalculating aspect-ratio changes
Add comments
Check crop width and height considering scalefactor
Use contentWidth in crop-selection