Merge pull request #123 from inthause/documents

Add PluginManager and remove PackageManager
Changed login URL (/login). Added Clipboard (/clipboard).
Fixed pagination in tree nodes.
Refactoring.
Added advanced filters in textbox (label=blabla & pathPart=fr).
Fixed layout issue on small devices.
Many UI fixes and enhancements.
Fixed documentURL filter when the input is not a document.
Styles.
Cleaning.
Server now sends the information about sortable columns.
Fixed help (correction and status).
Fixed sortable columns.
Fixed highlighted elements size.
Added drag and drop support to reorder the items in TokenList.
Removed settings button.
Changed colors and fixed margins.
Fixed filter operator (contains instead of eq) when filtering on strings.
Changed template file for documentListToolbar directive (twig).
Added "reorder" action to reorganize elements in a tree.