Support Notebook integration testing by adding APIs & fixing others (#3848)

- Added `runCell` API. Updated runCell button to listen to events on the model so it'll reflect run cell when called from other sources
- Plumbed through kernelspec info to the extension side so when changed, it's updated
- Fixed bug in ConnectionProfile where it didn't copy from options but instead overrode with empty wrapper functions

Here's the rough test code (it's in the sql-vnext extension and will be out in a separate PR)
```ts

    it('Should connect to local notebook server with result 2', async function() {
        this.timeout(60000);
        let pythonNotebook = Object.assign({}, expectedNotebookContent, { metadata: { kernelspec: { name: "python3", display_name: "Python 3" }}});
        let uri = writeNotebookToFile(pythonNotebook);
        await ensureJupyterInstalled();

        let notebook = await sqlops.nb.showNotebookDocument(uri);
        should(notebook.document.cells).have.length(1);
        let ran = await notebook.runCell(notebook.document.cells[0]);
        should(ran).be.true('Notebook runCell failed');
        let cellOutputs = notebook.document.cells[0].contents.outputs;
        should(cellOutputs).have.length(1);
        let result = (<sqlops.nb.IExecuteResult>cellOutputs[0]).data['text/plain'];
        should(result).equal('2');

        try {
            // TODO support closing the editor. Right now this prompts and there's no override for this. Need to fix in core
            // Close the editor using the recommended vscode API
            //await vscode.commands.executeCommand('workbench.action.closeActiveEditor');
        }
        catch (e) {}
    });

    it('Should connect to remote spark server with result 2', async function() {
        this.timeout(240000);
        let uri = writeNotebookToFile(expectedNotebookContent);
        await ensureJupyterInstalled();

        // Given a connection to a server exists
        let connectionId = await connectToSparkIntegrationServer();

        // When I open a Spark notebook and run the cell
        let notebook = await sqlops.nb.showNotebookDocument(uri, {
            connectionId: connectionId
        });
        should(notebook.document.cells).have.length(1);
        let ran = await notebook.runCell(notebook.document.cells[0]);
        should(ran).be.true('Notebook runCell failed');

        // Then I expect to get the output result of 1+1, executed remotely against the Spark endpoint
        let cellOutputs = notebook.document.cells[0].contents.outputs;
        should(cellOutputs).have.length(4);
        let sparkResult = (<sqlops.nb.IStreamResult>cellOutputs[3]).text;
        should(sparkResult).equal('2');

        try {
            // TODO support closing the editor. Right now this prompts and there's no override for this. Need to fix in core
            // Close the editor using the recommended vscode API
            //await vscode.commands.executeCommand('workbench.action.closeActiveEditor');
        }
        catch (e) {}
    });
});
```

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

@@ -123,7 +123,6 @@ export class NotebookComponent extends AngularDisposable implements OnInit, OnDe
 	ngOnInit() {
 		this._register(this.themeService.onDidColorThemeChange(this.updateTheme, this));
 		this.updateTheme(this.themeService.getColorTheme());
-		this.notebookService.addNotebookEditor(this);
 		this.initActionBar();
 		this.doLoad();
 	}
@@ -135,7 +134,7 @@ export class NotebookComponent extends AngularDisposable implements OnInit, OnDe
 		}
 	}
 
-	public get model(): NotebookModel {
+	public get model(): NotebookModel | null {
 		return this._model;
 	}
 
@@ -222,6 +221,9 @@ export class NotebookComponent extends AngularDisposable implements OnInit, OnDe
 			this.setViewInErrorState(localize('displayFailed', 'Could not display contents: {0}', error));
 			this.setLoading(false);
 			this._modelReadyDeferred.reject(error);
+		} finally {
+			// Always add the editor for now to close loop, even if loading contents failed
+			this.notebookService.addNotebookEditor(this);
 		}
 	}
 
@@ -538,4 +540,15 @@ export class NotebookComponent extends AngularDisposable implements OnInit, OnDe
 		this._model.pushEditOperations(edits);
 		return true;
 	}
+
+	public async runCell(cell: ICellModel): Promise<boolean> {
+		await this.modelReady;
+		let uriString = cell.cellUri.toString();
+		if (this._model.cells.findIndex(c => c.cellUri.toString() === uriString) > -1) {
+			return cell.runCell(this.notificationService);
+		} else {
+			return Promise.reject<boolean>(new Error(localize('cellNotFound', 'cell with URI {0} was not found in this model', uriString)));
+		}
+	}
+
 }