Add Change Password Feature

[vicky-gonsalves]

User should be able to change password.

** Requirements**

• 1. POST API should accept following headers and parameters:

// Headers:
bearer token in the auth headers - we generated from the reset-password api

// POST body should have these parameters:
newPassword:'SomenEWpAssWord'  

• 2. Create a new service in auth.service.ts to change the password:
  It should first verify the auth token and if its valid and not expired, we should straight away update user's password with new AES_ENCRYPTED password and respond back with 200 HTTP status