API - Expose ChartVersion Readme through chart-specific version API

[migmartri]

Readme API exposure

The UI requires the retrieval of a README file content in order to render it.

Since the Readme file content can change from version to version, its content should come in the chartVersion API call /charts/{repo}/{chartName}/versions and /charts/{repo}/{chartName}/versions/{version}

Maybe we should not add the readme file content to the listing of ChartVersions (/charts/{repo}/{chartName}/versions) in order to not overload the API call.

Readme importation

As discussed here, the Readme file for now is not going to be exposed in the index.yaml file but it is part of the tgz file, so we would need to do some "extra work" during chart versions ingestion.