Add a simple password strength label

[mrcnk]

Acceptance Criteria:

• [ ] The initial screen of both Create Wallet and Restore Wallet has a password strength indicator.
• [ ] It uses zxcvbn or similar library to determine the strength of a password.
• [ ] There should be 3 states of password strength:
  • weak - "Your password is terrible" (#EB6F92 - red)
  • average - Your password could be better" (#F2BEBC - peach)
  • good - "Your password is safe" (#A3DBE4 - mint)

Design