Add workflow_type field

In preparation for droping the definition table this adds
a new workflow_type field and starts populating it with
data.  After updating the existing workflows to populate
their workflow_type field the next patch, which drops
the definition model, can be deployed.

Change-Id: I455bdc98326e16b0a42ee9793a761a5ae1774271
Merge "Add workflow_type field"