Time-based one-time password (TOTP) authentication for Angie.

The Time-based One-Time Password (TOTP) algorithm, provides a secure mechanism
for short-lived one-time password values, which are desirable for enhanced
security. This algorithm can be used across a wide range of network applications
ranging from remote Virtual Private Network (VPN) access, Wi-Fi network logon to
transaction-orientated Web applications.

The nginx-http-auth-totp module provides TOTP authentication for an Angie
server.