Refactor package list tables and methods

This change reconciles the previously separate concepts:

- `list_packages`, `list_packages_packrat` => `get_package_state`
- `PackageInfo`, `PackagePackratInfo` => `PackageInfo`
- Package `CellTable`, packages `DataGrid` => packages `DataGrid`


If there is an error then this ends up being null, which isn't checked for in PackageStateUpdater.onResponseReceived