Collection of improvements for entity data table

## Description

We recently implemented a new data table component for the streams, dashboards and saved searches overview.
This issue contains a collection of all issues which further improve its usage.

- [Include stream outputs in streams overview.](https://github.com/Graylog2/graylog2-server/issues/14206)
- [Display search syntax help for entity data tables based on API response.](https://github.com/Graylog2/graylog2-server/issues/14710)