fix(grid): more typing, few code enhacement #5460

Author: hanastasov

Diff for: CHANGELOG.md

@@ -17,6 +17,7 @@ All notable changes for each version of this project will be documented in this
 
 - `IgxGrid`, `IgxTreeGrid`, `IgxHierarchicalGrid`
     - **Behavioral Change** - Pinning columns is no longer automatically prevented when the pinning area would exceed the size of the grid.
+    - `igxGridState` directive added to make it easy for developers to save and restore the grid state. The directive exposes the `getState` and `setState` methods to save/restore the state and an `options` input property to exclude features.
 - `IgxCarousel`:
     - **Breaking Changes** -The carousel slides are no longer array, they are changed to QueryList.
     - **Behavioural change** - When slides are more than 5, a label is shown instead of the indicators. The count limit of visible indicators can be changed with the input `maximumIndicatorsCount`

Diff for: projects/igniteui-angular/src/lib/grids/grid/grid.component.ts

@@ -36,8 +36,6 @@ export interface IGroupingDoneEventArgs extends IBaseEventArgs {
     ungroupedColumns: Array<IgxColumnComponent> | IgxColumnComponent;
 }
 
-export const INTERFACE_TOKEN = new InjectionToken<GridType>('GridTypeToken');
-
 /**
  * **Ignite UI for Angular Grid** -
  * [Documentation](https://www.infragistics.com/products/ignite-ui-angular/angular/components/grid.html)
@@ -68,10 +66,6 @@ export const INTERFACE_TOKEN = new InjectionToken<GridType>('GridTypeToken');
         IgxColumnResizingService,
         IgxForOfSyncService,
         IgxForOfScrollSyncService,
-        {
-            provide: INTERFACE_TOKEN,
-            useExisting: forwardRef( () => IgxGridComponent)
-        },
         IgxRowIslandAPIService
     ],
     selector: 'igx-grid',

Diff for: projects/igniteui-angular/src/lib/grids/index.ts

@@ -10,3 +10,4 @@ export * from './grid-common.module';
 export { IColumnVisibilityChangedEventArgs } from './hiding/column-hiding-item.directive';
 export * from './hiding/column-hiding.component';
 export * from './pinning/column-pinning.component';
+export * from './state.directive';