Add YubiKey OTP Support #39
Description
Add support for YubiKey's OTP. This would of course be in addition to the normal password (maybe have and option that the user can disable password?) As for database changes, new table called dan_yubikey_id with two columns id and uid. The id column will hold the unique piece of the OTP while the uid will be a foreign key to the user table id column. Setup will be in the settings tab and by default will be voluntary for each user. Perhaps make a config option to force YubiKey use. Extra configuration options include
"yubikeyOtp" => [
"enable" => true,
"clientId" => "",
"secretKey" => "",
"servers" => [], // By default use Yubico's cloud servers
"useHttps" => true,
"validateHttps" => true
]An extra textbox would show up on the login page for users that have two factor enabled and the OTP would be sent with the password and username.