Add settings for CAPTCHA in account recovery.

Allowing users to enable it and specify the site and secret key to use
with reCAPTCHA.

The old hard-coded keys were insecure; the secret key must not be
distributed publicly. The current defaults are the test keys provided at
https://developers.google.com/recaptcha/docs/faq#id-like-to-run-automated-tests-with-recaptcha-v2-what-should-i-do

Signed-off-by: Peter Marheine <peter@taricorp.net>

airsonic-main/src/main/webapp/WEB-INF/jsp/advancedSettings.jsp

@@ -91,7 +91,34 @@
                 <c:import url="helpToolTip.jsp"><c:param name="topic" value="smtpCredentials"/></c:import>
             </td>
         </tr>
+    </table>
 
+    <table class="indent">
+        <tr>
+            <td colspan="2">
+                <form:checkbox path="captchaEnabled" id="enablecaptcha" cssclass="checkbox"/>
+                <label for="enablecaptcha">
+                    <fmt:message key="advancedsettings.enableCaptcha"/>
+                </label>
+                <c:import url="helpToolTip.jsp"><c:param name="topic" value="captcha"/></c:import>
+            </td>
+        </tr>
+
+        <tr>
+            <td><fmt:message key="advancedsettings.recaptchaSiteKey"/></td>
+            <td>
+                <form:input path="recaptchaSiteKey" size="50"/>
+                <c:import url="helpToolTip.jsp"><c:param name="topic" value="recaptchaSiteKey"/></c:import>
+            </td>
+        </tr>
+
+        <tr>
+            <td><fmt:message key="advancedsettings.recaptchaSecretKey"/></td>
+            <td>
+                <form:input path="recaptchaSecretKey" size="50"/>
+                <c:import url="helpToolTip.jsp"><c:param name="topic" value="recaptchaSecretKey"/></c:import>
+            </td>
+        </tr>
     </table>
 
     <table class="indent"><tr><td>
@@ -152,4 +179,4 @@
     </script>
 </c:if>
 
-</body></html>
+</body></html>