Password Hashing & Authentication Integration

Implement feature related to issue #40 (https://github.com/vitalidze/traccar-web/issues/40#issuecomment-64164343) and Password Hashing mechanism so that the plain password never travels plain text).
OK, going to change that.

Btw and just as side note, in my past works (no java related) I usually used variable names different between GET/POST and "inner" logic. That way a little more security was added (because the "inner variable names" were not disclosed.