Add control columns to EuiDataGrid (#2846)

* Added action column type to EuiDataGrid; created a row selection demo

* Renamed action columns to control columns, finished functionality, demo, and docs

* Don't allow control columns to be expandable

* Added a render test for data grid control columns

* allow classNames on more inner grid components and make truncation skip control columns

* snaps

* flyout example

* removed selection highlighting from demo

* cleanup docs and styling

* undo an accidental change that snuck in

* changelog

* fix docs

* AriaAttributes instead of HTMLAttribute<T> to access aria attributes

Co-authored-by: dave.snider@gmail.com <dave.snider@gmail.com>

CHANGELOG.md

@@ -4,6 +4,7 @@
 - Exported `EuiSelectOptionProps` type ([#2830](https://github.com/elastic/eui/pull/2830))
 - Added `paperClip` glyph to `EuiIcon` ([#2845](https://github.com/elastic/eui/pull/2845))
 - Added `banner` prop to `EuiFlyoutBody` and updated `euiOverflowShadow` mixin ([#2837](https://github.com/elastic/eui/pull/2837))
+- Added control columns to `EuiDataGrid` to support non-data columns like row selection and actions ([#2846](https://github.com/elastic/eui/pull/2846))
 
 **Bug fixes**
 

src-docs/src/routes.js

@@ -79,6 +79,7 @@ import { DataGridExample } from './views/datagrid/datagrid_example';
 import { DataGridMemoryExample } from './views/datagrid/datagrid_memory_example';
 import { DataGridSchemaExample } from './views/datagrid/datagrid_schema_example';
 import { DataGridStylingExample } from './views/datagrid/datagrid_styling_example';
+import { DataGridControlColumnsExample } from './views/datagrid/datagrid_controlcolumns_example';
 
 import { DatePickerExample } from './views/date_picker/date_picker_example';
 
@@ -341,6 +342,7 @@ const navigation = [
       DataGridMemoryExample,
       DataGridSchemaExample,
       DataGridStylingExample,
+      DataGridControlColumnsExample,
       TableExample,
     ].map(example => createExample(example)),
   },