Add two_factor_totp_title filter to allow TOTP title to be changed by…

… site-owner (#294)

Props @BrookeDot

providers/class.two-factor-totp.php

@@ -80,12 +80,13 @@ public function user_two_factor_options( $user ) {
 		<?php if ( empty( $key ) ) :
 			$key = $this->generate_key();
 			$site_name = get_bloginfo( 'name', 'display' );
+			$totp_title = apply_filters( 'two_factor_totp_title', $site_name . ':' . $user->user_login, $user );
 			?>
 			<p>
 				<?php esc_html_e( 'Please scan the QR code or manually enter the key, then enter an authentication code from your app in order to complete setup.', 'two-factor' ); ?>
 			</p>
 			<p>
-				<img src="<?php echo esc_url( $this->get_google_qr_code( $site_name . ':' . $user->user_login, $key, $site_name ) ); ?>" id="two-factor-totp-qrcode" />
+				<img src="<?php echo esc_url( $this->get_google_qr_code( $totp_title, $key, $site_name ) ); ?>" id="two-factor-totp-qrcode" />
 			</p>
 			<p>
 				<code><?php echo esc_html( $key ); ?></code>