Send email action, part 2

Added send_email to action types and action factory.
Now it works end-to-end.

NOTE:this renames DSL from action.parameters.responce
to action.output. Other projects will need to adjust.

Tested manually with mistral-extra/examples/webhooks/cmd/run.py,
It works, almost:  except a bug causing exception on parsing out results.
In discussion, but a fix should go in separate commit.

Also, small fixes:
action_factory:31 - used to blow up when action has no 'parameters'
dsl.py:32 - return details on parsing errors (error, line, column)
api/config.py - deleted: not used

Change-Id: Ie7079eb9589c23cc6704f8e8739af67a635f1c77
Merge "Send email action, part 2"