Need to set dynamic learninglocker password

LL currently deploys with a pre-hashed password ('Tunapanda2') in `[templates/collections/users.json](https://github.com/tunapanda/provision/blob/master/playbooks/roles/learninglocker/templates/collections/users.json)`.  Need to figure out the best way to dynamically generate such a hash and put it into the db record. 
