Fixed chunking and insufficient storage check

- fixed free space detection based on the already uploaded chunks
- now deleting chunks as soon as it is read out before writing it into
  the part file, which reduces the space needed when assembling part
files
Makes #app-navigation a part of app management.
Adds Style changes to app-navigation in core/css/apps.css
idn_to_ascii is only used if available
Give storages the option to implement the getById behaviour for View->getPath
Implement getPath for shared files
Removes highlighting of selected items, padding from apps management.
merge CSS rules
Improve phpdoc
apply proposed change
external storage: change confusing 'applicable' to 'available for'
external storage: set storages to be available for All Users by default
Fix dirInfo check when dir does not exist
Merge pull request #7696 from owncloud/chunk-remainingspacefix

Fixed chunking and insufficient storage check
Fixed broken delete file action
Merge pull request #7984 from owncloud/wording-applicable2

External Storage: change confusing 'applicable' to 'available for', default to »All Users«
Merge pull request #7986 from owncloud/files-fixredirectwhendirnotexists

Fix dirInfo check when dir does not exist
Remember before change works better
Merge pull request #7997 from owncloud/correct-remember-trashbin-state

Correct the remembering of the trashbin app state in encryption test
Merge pull request #7817 from owncloud/app-navigation-for-apps

Makes #app-navigation a part of app management.