Generates random passwords containing at least one lowercase letter, one uppercase letter, one digit and one special character.

All randomness comes from :crypto.strong_rand_bytes/1 (through :crypto.rand_seed_s/0), so the passwords are suitable for credentials. The caller's :rand seed is not touched.

alias BoxTurtle.Security.Password

{:ok, password} = Password.generate(16)
String.length(password)  #=> 16
{:error, :too_short} = Password.generate(4)

# e.g. a temporary password for an account created by an admin
def create_invited_user(attrs) do
  {:ok, password} = Password.generate(20)
  attrs |> Map.put(:password, password) |> MyApp.Accounts.register_user()
end

The approach is inspired by the Rosetta Code Password generator task.