Add filter to AccountFilter (#2968)

app/views/admin/accounts/index.html.haml

@@ -20,6 +20,21 @@
       %li= filter_link_to t('admin.accounts.order.alphabetic'), recent: nil
       %li= filter_link_to t('admin.accounts.order.most_recent'), recent: '1'
 
+= form_tag(admin_accounts_url, { method: 'GET', class: 'simple_form' }) do
+  .fields-group
+    - Admin::FilterHelper::ACCOUNT_FILTERS.each do |key|
+      - if params[key].present?
+        = hidden_field_tag key, params[key]
+
+    - %i(username display_name email ip).each do |key|
+      .input.string.optional
+        .label_input
+          %label.string.optional= t("admin.accounts.#{key}")
+          = text_field_tag key, params[key], class: 'string optional'
+
+    .actions
+      %button.btn= t('admin.accounts.search')
+
 %table.table
   %thead
     %tr