Docs: adding first version of the auto-generated packages API docs. (#22107)

* trying out api-extractor.

* works with our setup of build.

* wip.

* changed the packages so it works better with the api-extractor.

* Changes to make the api-extractor to work.

* cleaned up the api-extractor config files.

* added some more documentation.

* added tsdoc-metadata to gitignore.

* removed the generated docs (will do that in another PR).

* added execute permission to script for generating dosc.

* added so we will push generated docs to branch.

* will clean packages_api on abort.

* Fixed failing tests.

* fixed formatting issue with typedoc comment.

* temporarily disabled tslint rules about namespace until https://github.com/microsoft/rushstack/issues/1029 is resolved

* temporary enabled bable namespaces.

* updated build script.

* updated script.

* updated script with some colors.

* changed to camelCase.

* removed spacing.

* Starting to add documentation guidelines.

* added examples headline.

* added menu options.

* added parameters and return values.

* Fixed merge error.

* Added first version of auto-generated docs.

* changed so we use the eslint ignore syntax.

* changed to correct eslint ingnore comment.

* fixed some spelling errors reported by codespell.

* added script to generate docs in current folder.

* updated api docs.

* lerna bootstrap.

* added eror to the ingore words list.

* removed file that should be ignored.

* updated locKFILE.

* referenced the code comments guidelines.

* updated packages.

* updated deps.

* updated the autogenerated dosc.

* adding missing new line.

docs/sources/packages_api/runtime/datasourcewithbackend.md

@@ -0,0 +1,100 @@
++++
+# -----------------------------------------------------------------------
+# Do not edit this file. It is automatically generated by API Documenter.
+# -----------------------------------------------------------------------
+title = "DataSourceWithBackend"
+keywords = ["grafana","documentation","sdk","@grafana/runtime"]
+type = "docs"
+draft = true
++++
+
+## DataSourceWithBackend class
+
+<b>Signature</b>
+
+```typescript
+export declare class DataSourceWithBackend<TQuery extends DataQuery = DataQuery, TOptions extends DataSourceJsonData = DataSourceJsonData> extends DataSourceApi<TQuery, TOptions> 
+```
+<b>Import</b>
+
+```typescript
+import { DataSourceWithBackend } from '@grafana/runtime';
+```
+<b>Constructors</b>
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [constructor(instanceSettings)](#constructor-instancesettings) |  | Constructs a new instance of the <code>DataSourceWithBackend</code> class |
+
+<b>Methods</b>
+
+|  Method | Modifiers | Description |
+|  --- | --- | --- |
+|  [query(request)](#query-method) |  | Ideally final -- any other implementation would be wrong! |
+|  [testDatasource()](#testdatasource-method) |  |  |
+|  [toDataQueryResponse(rsp)](#todataqueryresponse-method) |  | This makes the arrow library loading async. |
+
+### constructor(instanceSettings)
+
+Constructs a new instance of the `DataSourceWithBackend` class
+
+<b>Signature</b>
+
+```typescript
+constructor(instanceSettings: DataSourceInstanceSettings<TOptions>);
+```
+<b>Parameters</b>
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  instanceSettings | <code>DataSourceInstanceSettings&lt;TOptions&gt;</code> |  |
+
+### query method
+
+Ideally final -- any other implementation would be wrong!
+
+<b>Signature</b>
+
+```typescript
+query(request: DataQueryRequest): Observable<DataQueryResponse>;
+```
+<b>Parameters</b>
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  request | <code>DataQueryRequest</code> |  |
+
+<b>Returns:</b>
+
+`Observable<DataQueryResponse>`
+
+### testDatasource method
+
+<b>Signature</b>
+
+```typescript
+testDatasource(): Promise<{}>;
+```
+<b>Returns:</b>
+
+`Promise<{}>`
+
+### toDataQueryResponse method
+
+This makes the arrow library loading async.
+
+<b>Signature</b>
+
+```typescript
+toDataQueryResponse(rsp: any): Promise<DataQueryResponse>;
+```
+<b>Parameters</b>
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  rsp | <code>any</code> |  |
+
+<b>Returns:</b>
+
+`Promise<DataQueryResponse>`
+