[IMP] web: many2many editable list with X remove icon (#20978)

In many2many lists, the remove record from the widget is a trash bin.
It is confusing, as people feel they are deleting it when they are
only unlinking it.

So in many2many, we propose to change the trash icon by a 'X'.

This icon appears in many2many relations and in many2many widgets:
even though hr.expense.sheet defines the expense lines as a one2many,
it uses a many2many widget, so we use a 'X' instead of the trash bin.

To avoid ambiguity, we decided to rename 'delete' to 'remove'.

addons/web/static/src/less/list_view.less

@@ -66,7 +66,7 @@
         }
     }
 
-    .o_list_record_selector, .o_list_record_delete, .o_handle_cell {
+    .o_list_record_selector, .o_list_record_remove, .o_handle_cell {
         width: 1px;  // to prevent the column to expand
     }