add 2FA mechanism, fixes #547

Signed-off-by: Michael Kaufmann <d00p@froxlor.org>

templates/Sparkle/2fa/entercode.tpl

@@ -0,0 +1,26 @@
+$header
+	<article class="login bradius">
+		<header class="dark">
+			<img src="{$header_logo}" alt="Froxlor Server Management Panel" />
+		</header>
+			<section class="loginsec">
+				<form method="post" action="{$filename}" enctype="application/x-www-form-urlencoded">
+					<fieldset>
+					<legend>Froxlor&nbsp;-&nbsp;{$lng['login']['2fa']}</legend>
+					<p>
+						<label for="2fa_code">{$lng['login']['2facode']}:</label>&nbsp;
+						<input type="text" name="2fa_code" id="2fa_code" value="" required/>
+					</p>
+					<p class="submit">
+						<input type="hidden" name="action" value="2fa_verify" />
+						<input type="hidden" name="send" value="send" />
+						<input type="submit" value="{$lng['2fa']['2fa_verify']}" />
+					</p>
+					</fieldset>
+				</form>
+				<aside>
+					<a href="index.php">{$lng['login']['backtologin']}</a>
+				</aside>
+			</section>
+	</article>
+$footer