Password Strength Meter (Progressive Enhancement)

[nelsonic]

At present (during MVP) we do not have any checks for the length or strength of passwords.
This is obviously undesirable as

I propose that we add a client-side enhancement to the password_create.html.eex template with:

• Tips for good passwords (passphrases) using multiple words.
• Visual strength meter
  
• Disable the submit button until the password meets desired standard?

Read:

• https://www.troyhunt.com/password-strength-indicators-help-people-make-dumb-choices

This is related to but distinct from #65 (Show Password in Plaintext in Creation Form)