Add support for data_partials in outcomes.

This will render a given partial assigning a given variable as a local.  Partials will be looked for in FLOW_DIR/data_partials/
Switch lost or stolen passport to use data_partials

This was the only flow using the contact_list functionality, so this will enable it to be removed.
Remove contact_list feature

This is no longer used, and quite restrictive.  It's been superseded by the data_partials feature which is a lot more flexible.

This also removes the half-implemented places feature that's not been finished in over a year.
Merge pull request #330 from alphagov/data_partials

Add support for rendering partials in outcomes.