FILEMAN-27: Implement a widget to display the tree of folders from a drive
* Rename 'jobId' parameter to 'id' as the 'data=jobStatus' already implies that the request is about a job
* Use the doc name (WebHome) as drive id in order to be consistent with the folder id
* Display a root node corresponding to the drive; its child nodes are the root folders and the meta nodes
* Select the node specified on the request only if it still exists
* Enable the context menu on the folder tree
* Add a readOnly flag to prevent modifications on the tree while a job is in progress
* Prevent nested (Angular) $apply calls when a tree node is selected
* Add support for create, remane and delete folders through the context menu
* Improve the style of the folder tree
* Retrieve the job status through the drive document instead of the current folder because the current folder can be renamed/deleted by the currently running job (while the drive document shouldn't be affected by the jobs)