Publish student-finance-forms (smartdown edition)

The smartdown implementation of student finance forms has been tested
and are feature complete with the original rb/yml implementation.

* Remove the -transtion suffix, which distinguished it from the
  original version
* Change status to published
Delete original student finance flow

Now there the smartdown implmentation is complete.

 - remove the logic, copy and test
 - do the same for an old v2 that's knocking around
Merge pull request #1157 from alphagov/publish-student-finance-smartdown

Publish smartdown version of Student Finance Forms