Added Buy Me A Coffee button

Added new Buy Me A Coffee button using the color palette and assets from the official  Buy Me A Coffee creator kit.

index.html

@@ -335,6 +335,11 @@
             src="images/icons/web.svg" alt="Web Logo">Website</a>
         <br>
 
+        <!-- Buy Me a Coffee -->
+        <a class="button button-coffee" href="#" target="_blank" rel="noopener"><img class="icon"
+            src="images/icons/coffee.svg" alt="Buy Me a Coffee">Buy Me a Coffee</a>
+        <br>
+
         <br>
         <p>Build your own by forking <a href="https://littlelink.io" target="_blank" rel="noopener">LittleLink</a>.</p>