Website: Add empty state to query library (#14144)

Closes: #13223

Changes:
- Added an empty state that is shown to users when no query matches
their selected filters.

website/assets/styles/pages/query-library.less

@@ -67,6 +67,14 @@
       line-height: 18px;
     }
   }
+  [purpose='query-list-empty-state'] {
+    margin-top: 40px;
+    margin-right: 30px;
+    margin-left: 30px;
+    a {
+      font-size: 16px;
+    }
+  }
 
   .input-group {
     &.search {

website/views/pages/query-library.ejs

@@ -139,6 +139,9 @@
               <div class="divider"></div>
             </div>
           </div>
+          <div purpose="query-list-empty-state" v-if="queriesList.length === 0">
+            <p class="mb-0">There are no results that match your filters. <a target="_blank" href="https://github.com/fleetdm/fleet/edit/main/docs/01-Using-Fleet/standard-query-library/standard-query-library.yml">Everyone can contribute</a>.</p>
+          </div>
         </div>
       </div>
     </div>