Port most notebook model code over to be behind a service (#3068)

- Defines a new NotebookService in Azure Data Studio which will be used to interact with notebooks. Since notebooks can require per-file instantiation the provider is just used to create & track managers for a given URI.
- Inject this into notebook.component.ts and pass required parameters that'll be used to properly initialize a manger into the method. Actual initialization not done yet.
- Port over & recompile notebook model code
- Define most required APIs in sqlops.proposed.d.ts. In the future, these will be used by extensions to contribute their own providers.

src/sql/parts/notebook/cellViews/code.component.ts

@@ -11,7 +11,6 @@ import { AngularDisposable } from 'sql/base/common/lifecycle';
 import { ComponentBase } from 'sql/parts/modelComponents/componentBase';
 import { IComponent, IComponentDescriptor, IModelStore, ComponentEventType } from 'sql/parts/modelComponents/interfaces';
 import { QueryTextEditor } from 'sql/parts/modelComponents/queryTextEditor';
-import { ICellModel } from 'sql/parts/notebook/cellViews/interfaces';
 
 import { IColorTheme, IWorkbenchThemeService } from 'vs/workbench/services/themes/common/workbenchThemeService';
 import * as themeColors from 'vs/workbench/common/theme';
@@ -26,6 +25,7 @@ import { Schemas } from 'vs/base/common/network';
 import * as DOM from 'vs/base/browser/dom';
 import { IModeService } from 'vs/editor/common/services/modeService';
 import { IModelService } from 'vs/editor/common/services/modelService';
+import { ICellModel } from 'sql/parts/notebook/models/modelInterfaces';
 
 export const CODE_SELECTOR: string = 'code-component';