Implement basic hashing

[Shadow53]

• Add necessary fields to the database
• Create hashing functions (Argon2i)
  • Generate a random salt
  • Generate a hash, given a password, salt, and hashing parameters
  • Given resource maxima, determine the most secure hashing parameters
    • This document outlines how to do that
• Create Warp `Filters
  • Create new user, given fields email, password, and confirm-password
    • If possible, disallow multiple accounts for the same email address by taking into account + suffixes on the email address, e.g. example+other@example.com
  • Get an Option<User> from a request using the Authorization header
  • Given the above Option<User>, respond to the client with a WWW-Authenticate header for paths where authentication is required (likely called like get_user().and(require_user))

Notes:

• A User struct should not contain authentication-only information, i.e. hashing parameters, salt, or hash
• All above functions, including Filters, must have unit tests