Copied from the mahara.org registration table. It stores each registration field
in a local database with a timestamp of when the data was obtained.

This storage is done whether or not the data is actually sent to mahara.org.

Change-Id: Ib8478b0caa97c5cc5f04a7d5b44f2a9ac11f9ce8
Signed-off-by: Hugh Davenport <hugh@catalyst.net.nz>