[IMP] web: set field_name data on search panel sections

adds field_name data on category and filter lists in the
search panel template so it can be used to identify their field.

this improvement is used in the drag & drop features introduced
in the documents search panel (https://github.com/odoo/enterprise/pull/4805).

Task: #1998014

closes odoo/odoo#34813

Signed-off-by: Martin Geubelle (mge) <mge@openerp.com>

addons/web/static/src/xml/kanban.xml

@@ -224,7 +224,7 @@
         <t t-call="SearchPanel.SectionHeader">
             <t t-set="section" t-value="category"/>
         </t>
-        <ul class="list-group d-block">
+        <ul class="list-group d-block o_search_panel_field" t-att-data-field-name="category.fieldName">
             <li class="o_search_panel_category_value border-0 list-group-item" t-att-data-category-id="category.id">
                 <header t-att-class="'list-group-item-action' + (!category.activeValueId ? ' active' : '')">
                     <label class="o_search_panel_label mb0 d-block">
@@ -262,7 +262,7 @@
         <t t-call="SearchPanel.SectionHeader">
             <t t-set="section" t-value="filter"/>
         </t>
-        <ul class="list-group d-block">
+        <ul class="list-group d-block o_search_panel_field" t-att-data-field-name="filter.fieldName">
             <t t-if="filter.groups" t-call="SearchPanel.FilterGroups">
                 <t t-set="groups" t-value="filter.groups"/>
             </t>