Add atleast 6 characters limit/check as per susi ai for password setting and change.

[rupav]

I'm submitting a ... (check one with "x")

• [x] bug report
• [ ] feature request
• [ ] support request => Please do not submit support requests here, instead ask your query in out Gitter channel at https://gitter.im/fossasia/susi_server

Current behavior:

Currently while signing up, entering password with less than 6 characters, gives an alert of Sign up failed. Try again. Similarly, no error shows up while filling up Change Password field.

Expected behavior:

susi_chromebot should indicate atleast 6 character limit.

Steps to reproduce:

Try filling Signup or changing password when logged in by entering password less than 6 characters.

Would you like to work on the issue? Yes.

[rupav]

Desired behavior : https://chat.susi.ai/ indicates this on dashboard: Also the sign up page has indicator of this limit: