Password policy for users in Spock

System must be able to enforce a password policy rule for built-in users by the administrator. The details are specified in the RBAC PRD here - https://docs.google.com/document/d/1DtkJZdq7LxAHBezMga3Z2qA3bFjFh0WhypouWEEnMWU/edit

Minimum of six characters long (This is for backwards compat purposes) -> This is the default minimum but can be changed by the admin

A switch to enable the following :
Upper case alphabetic (A through Z (uppercase characters))
Lower case alphabetic a through z (lowercase characters)
Numeric 0 through 9 (numeric characters)
Special character (Special characters: ~, @, #, %, ^, ( ), -, _, { })

 
Old passwords get migrated without the rule in effect. Passwords that are newly created/rotated have to meet the rules