add select all|none links for [un]block version checkboxes (#20912)

src/olympia/blocklist/templates/admin/blocklist/includes/enhanced_blocks.html

@@ -22,6 +22,8 @@
       {% if block_obj.id %}
         <span class="existing_block">[<a href="{% url 'admin:blocklist_block_change' block_obj.id %}">Edit Block</a>]</span>
       {% endif %}
+      [<a href='#' class="select-all-versions">select all</a>]
+      [<a href='#' class="select-none-versions">select none</a>]
       <ul>
         {% for version in block_obj.addon_versions %}
           <li data-version-id="{{ version.id }}">

static/js/admin/blocklist_blocklistsubmission.js

@@ -1,6 +1,21 @@
 document.addEventListener('DOMContentLoaded', () => {
   'use strict';
 
+  const checkAllCheckboxes = (event) =>
+    event.target.parentElement
+      .querySelectorAll(`input[name="changed_version_ids"]`)
+      .forEach((checkbox) => checkbox.setAttribute('checked', true));
+  const clearAllCheckboxes = (event) =>
+    event.target.parentElement
+      .querySelectorAll(`input[name="changed_version_ids"]`)
+      .forEach((checkbox) => checkbox.removeAttribute('checked'));
+  document
+    .querySelectorAll('a.select-all-versions')
+    .forEach((a) => a.addEventListener('click', checkAllCheckboxes, true));
+  document
+    .querySelectorAll('a.select-none-versions')
+    .forEach((a) => a.addEventListener('click', clearAllCheckboxes, true));
+
   const enableIfChecked = (isChecked, fieldId) => {
     const field = document.querySelector(`#${fieldId}`);
     if (isChecked) {