Add initial submit-t2-signature JSON API and extend setup stuff

* Add initial submit-t2-signature API which calls Bj to add signature
  and possibly broadcast, then updates contract state in db.
* Add runtime_tools to mw app deps list.
* Add commented out prototype for forcing openssl to block for quality
  entropy bits (/dev/random).
* Increase contract setup concurrency hack from 4 to 6 processes.
Merge branch 'gustav/contracts10'

* gustav/contracts10:
  Add initial submit-t2-signature JSON API and extend setup stuff