Add and display staging path

refs #6248

Staging path will be used in future to store files being transferred
from one Space to another.
Make moving files more generic

refs #6248

Add functions to move files/folders to and from the storage service.
Moving to the storage service from the original location deposits them
in a staging area associated with the destination Space.  Moving from
the storage service to the final destination moves the file from the
destination Space's staging area to the destination path.  The staging
area is locally accessible to the storage service, which makes the move
to/from storage service functions much simpler than trying to move to
any protocol space.

Each protocol space implements these functions, and the parent Space
calls them as needed.  Several protocol spaces have similar
requirements, so helper functions were placed in the Space class for
moving locally (using os.rename) and rsync.

Update store_aip to use the new functions.
Staging path in default Space

refs #6248

Add staging path to default Space.  Only set the default transfer
source and AIP storage paths if they're unset.
Add backlog purpose

refs #6131
POST to Location moves files

refs #6131

POST to a Location with information about the source location and the paths
of the files to be moved, copies the listed files from the linked Location
to the Location POSTed to.  Directories are created with 775 permissions
instead of 755.
Add default backlog location

refs #6131

Add config option and default values for a default transfer backlog location.
Rsync copies folders

Recursive option added to rsync command to copy folders properly.  Execute
permissions left alone, as directories that don't have execute bit don't
display permissions.