Add search button to IL search

Author: nicolachr

app/views/issues/_import_box.html.erb

@@ -33,6 +33,7 @@
     <form action="<%=  static_issuelib_import_path %>" class="form-inline mb-4" method="get">
       <div class="inset-button-wrapper">
         <input type="text" class="form-control search-query", placeholder="Search Issue Library" />
+        <button type="submit" class="btn btn-primary">Search</button>
       </div>
     </form>
   <% else %>