ui: add support for casting columns to the table viewer

Allow the user to change the type of the column explicitly by
casting the column to one of the types in PerfettoSQL.

Author: altimin

ui/src/base/semantic_icons.ts

@@ -50,6 +50,7 @@ export class Icons {
   static readonly Check = 'check';
   static readonly Search = 'search';
   static readonly Save = 'save';
+  static readonly Undo = 'undo';
 
   // Page control
   static readonly NextPage = 'chevron_right';

ui/src/components/widgets/sql/pivot_table/pivot_table.ts

@@ -20,7 +20,7 @@ import {Button} from '../../../../widgets/button';
 import {Icons} from '../../../../base/semantic_icons';
 import {TableColumn, tableColumnId} from '../table/table_column';
 import {MenuDivider, MenuItem} from '../../../../widgets/menu';
-import {SelectColumnMenu} from '../table/select_column_menu';
+import {SelectColumnMenu} from '../table/menus/select_column_menu';
 import {SqlColumn} from '../table/sql_column';
 import {buildSqlQuery} from '../table/query_builder';
 import {Aggregation, AGGREGATIONS} from './aggregations';