allow setting password hash directly, in debug mode only.

* Accept password hashes directly when calling FacilityUser.set_password, but in debug mode only
* Migrated generatefakedata to use password hashes
* Added tests to validate that passwords can only be set via hash in debug mode.

@rtibbles, can you take a look at this? @jamalex, can you validate that the approach is ok from your security concerns?

This will also help resolve an outstanding branch related to generatefakedata.