Docs: Deprecating packages_api and removing it from our pipelines (#54473)

docs/sources/developers/plugins/add-support-for-explore-queries.md

@@ -73,4 +73,4 @@ const firstResult = new MutableDataFrame({
 });
 ```
 
-For possible options, refer to [PreferredVisualisationType](https://grafana.com/docs/grafana/latest/packages_api/data/preferredvisualisationtype/).
+For possible options, refer to [PreferredVisualisationType](https://github.com/grafana/grafana/blob/main/packages/grafana-data/src/types/data.ts#L25).

docs/sources/developers/plugins/migration-guide.md

@@ -732,9 +732,9 @@ Before 7.0, data source and panel plugins exchanged data using either time serie
 
 Grafana 7.0 is backward compatible with the old data format used in previous versions. Panels and data sources using the old format will still work with plugins using the new data frame format.
 
-The `DataQueryResponse` returned by the `query` method can be either a [LegacyResponseData](https://grafana.com/docs/grafana/latest/packages_api/data/legacyresponsedata/) or a [DataFrame](https://grafana.com/docs/grafana/latest/packages_api/data/dataframe/).
+The `DataQueryResponse` returned by the `query` method can be either a [LegacyResponseData](https://github.com/grafana/grafana/blob/main/packages/grafana-data/src/types/datasource.ts#L419) or a [DataFrame](https://github.com/grafana/grafana/blob/main/packages/grafana-data/src/types/dataFrame.ts#L200).
 
-The [toDataFrame()](https://grafana.com/docs/grafana/latest/packages_api/data/todataframe/) function converts a legacy response, such as `TimeSeries` or `Table`, to a `DataFrame`. Use it to gradually move your code to the new format.
+The [toDataFrame()](https://github.com/grafana/grafana/blob/main/packages/grafana-data/src/dataframe/processDataFrame.ts#L309) function converts a legacy response, such as `TimeSeries` or `Table`, to a `DataFrame`. Use it to gradually move your code to the new format.
 
 ```ts
 import { toDataFrame } from '@grafana/data';