Password Security Hardening and Change Password using UI

1. Password Security Hardening

Changed encryption algorithm to pbkdf2 with the following parameters:

Digest: sha512

Iterations: 600 000

2. User passwords upgrade path

Following Guardian instance upgrade, at the first login existing users are prompted to change the password which would be encrypted using the new method.

3. Change user password

Users can change passwords using the new option in their profile page.