muhhshoaib/security-change-user-password-requirements-685:changed user password requirement

muhhshoaib/security-change-user-password-requirements-685: handled password complexity scenarios messages according to Chris Suggestions

muhhshoaib/security-change-user-password-requirements-685: changed the chracteres storage from sets to lists
Merge pull request #59 from edx-solutions/muhhshoaib/security-change-user-password-requirements-685

Muhhshoaib/security change user password requirements 685