Add multiple captcha options for form submission

-Supported captchas include Google reCaptcha v3 (score-based), Google reCaptcha v2 (checkbox and invisible) and hCaptcha ("Always Challenge" mode)
-Captcha options are global to the explorer even though the only form submission page is the "Claim Address" feature which takes full advantage of the new captcha options

lib/settings.js

@@ -1212,7 +1212,10 @@ exports.claim_address_page = {
   "show_header_menu": true,
   // enable_bad_word_filter: Enable/disable the "bad word" filter for claimed addresses, so that trying to claim an address with a bad word like "ash0le" will fail
   //                         This feature uses the default blacklist from the "bad-words" plugin from here: https://www.npmjs.com/package/bad-words
-  "enable_bad_word_filter": true
+  "enable_bad_word_filter": true,
+  // enable_captcha: Enable/disable using captcha security when filling out and submitting the claim address form
+  //                 NOTE: you must also configure and enable one of the options in the main "captcha" settings for this option to function correctly
+  "enable_captcha": false
 };
 
 // orphans_page: a collection of settings that pertain to the orphans page
@@ -1273,6 +1276,51 @@ exports.sync = {
   "supply": "GETINFO"
 };
 
+// captcha: a collection of settings that pertain to the captcha security used by different elements of the explorer
+// NOTE: only 1 captcha option can be enabled and used at any given time. If you enable 2 or more options the explorer will use the first available enabled option it finds
+exports.captcha = {
+  // google_recaptcha3: a collection of settings that pertain to using Google reCAPTCHA v3. Signup to get your site and secret keys here: https://www.google.com/recaptcha/admin
+  "google_recaptcha3": {
+    // enabled: Enable/disable the use of Google reCAPTCHA v3 (true/false)
+    //          If set to false, Google reCAPTCHA v3 will be completely disabled as a security feature
+    "enabled": false,
+    // pass_score: A numeric score between 0.0 and 1.0 used to deteremine if a particular captcha request passed or failed
+    //             Google reCAPTCHA v3 returns a score value for every captcha request. 1.0 is very likely a good interaction whereas 0.0 is very likely a bot
+    //             Google recommends using 0.5 by default but you may increase the passing score if you are receiving too many automated bot submissions or lower the score if legitimate users are having troubles passing the captcha challenge
+    "pass_score": 0.5,
+    // site_key: Enter the SITE KEY value from your Google reCAPTCHA v3 settings here
+    "site_key": "",
+    // secret_key: Enter the SECRET KEY value from your Google reCAPTCHA v3 settings here
+    "secret_key": ""
+  },
+  // google_recaptcha2: a collection of settings that pertain to using Google reCAPTCHA v2. Signup to get your site and secret keys here: https://www.google.com/recaptcha/admin
+  "google_recaptcha2": {
+    // enabled: Enable/disable the use of Google reCAPTCHA v2 (true/false)
+    //          If set to false, Google reCAPTCHA v2 will be completely disabled as a security feature
+    "enabled": false,
+    // captcha_type: Determine the type of captcha to use for security validation
+    //               Valid options:
+    //               checkbox: The "I'm not a robot" Checkbox requires the user to click a checkbox indicating the user is not a robot. This will either pass the user immediately (with No CAPTCHA) or challenge them to validate whether or not they are human
+    //               invisible: The invisible reCAPTCHA badge does not require the user to click on a checkbox. By default only the most suspicious traffic will be prompted to solve a captcha
+    "captcha_type": "checkbox",
+    // site_key: Enter the SITE KEY value from your Google reCAPTCHA v2 settings here
+    "site_key": "",
+    // secret_key: Enter the SECRET KEY value from your Google reCAPTCHA v2 settings here
+    "secret_key": ""
+  },
+  // hcaptcha: a collection of settings that pertain to using hCaptcha. Signup to get your site and secret keys here: https://dashboard.hcaptcha.com/signup
+  //           NOTE: Only the free "Always Challenge" mode is currently supported
+  "hcaptcha": {
+    // enabled: Enable/disable the use of hCaptcha (true/false)
+    //          If set to false, hCaptcha will be completely disabled as a security feature
+    "enabled": false,
+    // site_key: Enter the SITE KEY value from your hCaptcha settings here
+    "site_key": "",
+    // secret_key: Enter the SECRET KEY value from your hCaptcha settings here
+    "secret_key": ""
+  }
+};
+
 // labels: a collection of settings that pertain to the list of customized wallet address labels
 //         Adding entries to this section will display a custom label beside each affected wallet address when displayed in the explorer
 //         NOTE: You can add as many address labels as desired