Secrets saver

[LLIo6oH]

Is your feature request related to a problem? Please describe. Feature to save passwords.

Features list

Split:

• save one piece of a secret in local data storage. It must be encrypted by the user's RSA key
• distribute other pieces of the password across the cluster
• create a new record in the "meta-password" table on the server by using the distribute endpoint

Recover:

• device1 sends a request to recover the password
• device2 gets a recover request, then:
  • decrypts its share of the secret
  • encrypts the share with device1 RSA public key
  • sends to device1
  • same steps for the device if necessary
  • device1 gets a response from device2
  • decrypts share2 of the password with its private RSA key
  • combine shares and recover the password

Linked issue https://github.com/meta-secret/meta-secret-mobile/issues/3