Support output renderers via Angular contributions (#6146)

- Added a registry for output components
- Refactored existing renderers to plug in via Angular
- Added Markdown renderer using new Angular contribution point
- Added support to notebook module to dynamically load new components

src/sql/platform/dashboard/common/modelComponentRegistry.ts

@@ -6,8 +6,6 @@ import { Type } from '@angular/core';
 import { ModelComponentTypes } from 'sql/workbench/api/common/sqlExtHostTypes';
 
 import * as platform from 'vs/platform/registry/common/platform';
-import { IJSONSchema } from 'vs/base/common/jsonSchema';
-import * as nls from 'vs/nls';
 import { IComponent } from 'sql/workbench/electron-browser/modelComponents/interfaces';
 
 export type ComponentIdentifier = string;