feat(contact-form): add consent checkbox for data processing agreement

templates/embed_contact.html

@@ -22,6 +22,12 @@
           <label for="message">Message:</label>
           <textarea id="message" name="message" required></textarea>
         </div>
+        <div class="form-group">
+          <label for="consent"
+            >I agree to the processing of my submitted data.</label
+          >
+          <input type="checkbox" id="consent" name="consent" required />
+        </div>
         <button type="submit">Send Message</button>
       </form>
       <div id="responseMessage"></div>