Adds support for sha512 password hashing

[kapeels]

First Ohmage PR! 😎

Adds support for SHA512 password hashing.

Tested the following scenarios:

1. Creating new user as admin
2. Changing user password as admin
3. Setting up user as admin
4. Changing user password on login (for forced password change feature) as end user
5. Creating new user by self-registration
6. Resetting password as end user

[stevenolen]

are you able to add the new deps as a jar instead?

[kapeels]

Done! Check it out.