Automate Transfers: Track transfer info in DB

Use SQLite DB to track information about previous and current transfers and
use that list to decide what to start as the next transfer.
Automate Transfers: Remove cwd hack
Automate Transfers: Add another pre-transfer script

refs #7369

Create metadata.json based on directory name.
Automate Transfers: Can start transfers from subdir of ts_path

Add ability to start transfers from directories that are not the immediate
children of ts_path.  Depth param specifies how many directories to go down
before creating transfers.  Default is 1, which mimics old behaviour and
creates transfers from the children of ts_path.