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/resources/org/airsonic/player/i18n/ResourceBundle_en.properties

@@ -338,6 +338,9 @@ advancedsettings.smtpEncryption.none=None
 advancedsettings.smtpEncryption.starttls=STARTTLS
 advancedsettings.smtpEncryption.ssl=SSL/TLS
 advancedsettings.smtpFrom=E-mail sender
+advancedsettings.enableCaptcha=Require CAPTCHA for account recovery
+advancedsettings.recaptchaSiteKey=reCAPTCHA site key
+advancedsettings.recaptchaSecretKey=reCAPTCHA secret key
 # personalSettings.jsp
 personalsettings.title=Personal settings for {0}
 personalsettings.language=Language
@@ -730,6 +733,12 @@ helppopup.smtpEncryption.title=SMTP Encryption
 helppopup.smtpEncryption.text=<p>Encryption method used for connections to the SMTP server. Choose "None" for no encryption.</p>
 helppopup.smtpFrom.title=From address
 helppopup.smtpFrom.text=<p>The sender address for e-mails originating from the Airsonic server. Must be a valid e-mail address.</p>
+helppopup.captcha.title=CAPTCHA
+helppopup.captcha.text=<p>When enabled, users must solve a CAPTCHA to prove they are human when requesting a password reset.</p> <p>Requires registration with an external service; see the <a href="https://airsonic.github.io/docs/captcha/">documentation</a>.</p>
+helppopup.recaptchaSiteKey.title=reCAPTCHA site key
+helppopup.recaptchaSiteKey.text=<p>A site key obtained from the reCAPTCHA admin console.</p>
+helppopup.recaptchaSecretKey.title=reCAPTCHA secret key
+helppopup.recaptchaSecretKey.text=<p>A secret key obtained from the reCAPTCHA admin console. Left unchanged if blank.</p>
 helppopup.scanMediaFolders.title=Media folders scanning rules
 helppopup.scanMediaFolders.text=<p>Note that subfolder names starting with a dot (.) or @eaDir, as well as Thumbs.db files, are ignored.</p>
 # wap/index.jsp