Describe events in `dstack` docs — possibly on separate Concepts page. Consider including: - Description of what events and event targets are. - Viewing events in the UI. - Viewing events in the [CLI](https://dstack.ai/docs/reference/cli/dstack/event/). - Configuring events [TTL](https://dstack.ai/docs/reference/environment-variables/#DSTACK_SERVER_EVENTS_TTL_SECONDS). Also resolve this [TODO in the CLI reference](https://github.com/dstackai/dstack/blob/e74332adacb4a728cacbc8e719662e16ee058215/docs/docs/reference/cli/dstack/event.md?plain=1#L5).
Describe events in
dstackdocs — possibly on separate Concepts page.Consider including:
Also resolve this TODO in the CLI reference.