Add optional encoding parameter to getImageHTML method

The getImageHTML method in the Larvatar class now accepts an optional encoding parameter. When 'base64' is passed in as the encoding type, it generates a base64-encoded version of the image. In any other case, it generates the image without encoding.

src/Larvatar.php

@@ -35,15 +35,19 @@ public function __construct(string $name = '', string $email = '', int|LarvatarT
      * Generates the HTML or SVG code directly for usage
      * @return string HTML or SVG code
      */
-    public function getImageHTML(): string
+    public function getImageHTML(string $encoding = ''): string
     {
         if ($this->type == LarvatarTypes::InitialsAvatar) {
             $initial_avatar = new InitialsAvatar($this->name);
             if (isset($this->font) && $this->font != '' && $this->fontPath != '') {
                 $initial_avatar->setFont($this->font, $this->fontPath);
             }
             $initial_avatar->setSize($this->size);
-            return $initial_avatar->generate();
+            if ($encoding == 'base64') {
+                return '<img src="'.$initial_avatar->generate(encoding: $encoding).'" />';
+            } else {
+                return $initial_avatar->generate();
+            }
         }
 
         $gravatar = new Gravatar($this->email);