BUG: Searching for entities inside of a group

[tillprochaska]

Describe the bug When viewing a group index page (/groups/:id), a small blue callout is displayed at the top:

If you would like to search for specific entities or documents within the datasets that this group has access to, click here instead.

Clicking the link will navigate to a search where the "Datasets" facet is prepopulated with all datasets the group has access to. In some cases, there will quite a few (> 50) datasets the group has access to.

The search query will be extremely slow, timeout or might fail with a Bad Request response due to the request being too long.

Apart from that, the UI is not optimal, as a lot of screen space is occupied by the filters at the top of the search results page.

To Reproduce Steps to reproduce the behavior:

1. Go to a groups index page.
2. Click the on the link in the blue callout.

Expected behavior We should support filtering entities by groups. In the short term, we might want to consider displaying the callout only if the number of datasets the group has access to is below a certain threshold.