feat(client): add Patreon button (#44113)

* feat(add): add patreon button

* feat: add noreferrer

* Apply suggestions from code review

Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>

Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>

config/donation-settings.js

@@ -85,12 +85,13 @@ const paypalConfigurator = (donationAmount, donationDuration, paypalConfig) => {
   };
 };
 
-//
 const donationUrls = {
   successUrl: 'https://www.freecodecamp.org/news/thank-you-for-donating/',
   cancelUrl: 'https://freecodecamp.org/donate'
 };
 
+const patreonDefaultPledgeAmount = 500;
+
 module.exports = {
   durationsConfig,
   amountsConfig,
@@ -103,5 +104,6 @@ module.exports = {
   onetimeSKUConfig,
   paypalConfigTypes,
   paypalConfigurator,
-  donationUrls
+  donationUrls,
+  patreonDefaultPledgeAmount
 };