Support listening to Space updates

[Wauplin]

Space infra have a SSE endpoint to get updates on the status of a Space. It would be nice to have support for this endpoint to subscribe to space updates. This would have to be implemented as a Python generator.

Example for Open LLM Leaderboard:

• Space: https://huggingface.co/spaces/HuggingFaceH4/open_llm_leaderboard
• endpoint: https://api.hf.space/v1/HuggingFaceH4/open_llm_leaderboard/sse

First discussed on slack (internal) (cc @freddyaboulton @christophe-rannou)

Note: How much time the connection stays open when you start listening to the SSE endpoint? => Til the client breaks the connection or the server restarts, which happens every time we release, you'd need to handle a reconnect

[julien-c]

i'd say kinda low-prio but why not!