chef_wm_password supports both EC and OSC password data schemas

* Add support for EC/OSC sha1+bcrypt types
* support forlegacy sha1+salt types
* upgrade function
* tests for the above
* added a password test data generator rb file

ping @opscode/server-team 
This is re-adding what was removed a few PRs ago, before I realized we'd need to support both. I *think* 0.5.0 came originally from the bcrypt library version, but I'm not sure.  Since the name is something we that we control and the version is not significant to what we're doing, it would never change.