Fix #3420 Analyze in notebook doesn't include text (#3482)

- Add edit API that can be used in the extension
- Separated document and editor classes out since this is the point those get big. I can refactor back in if needed to ease code review
- Based this off text editing APIs but tweaked for the fact this is a cell/array based set of edits

src/sql/workbench/api/node/sqlExtHost.api.impl.ts

@@ -442,7 +442,8 @@ export function createApiFactory(
 				},
 				registerNotebookProvider(provider: sqlops.nb.NotebookProvider): vscode.Disposable {
 					return extHostNotebook.registerNotebookProvider(provider);
-				}
+				},
+				CellRange: sqlExtHostTypes.CellRange
 			};
 
 			return {