Support and document Hubs Community Edition

[Utopiah]

There is already a great "I want to use Immers Space with Mozilla Hubs Cloud" section.

Due to Mozilla stopping the support of Hubs https://hubs.mozilla.com/labs/sunset/ there is now a pressing effort to have Hubs Community Edition working on as many cloud provider as possible. The "usual" AWS example will not be the only one from now on and instead Community Edition https://github.com/mozilla/hubs-cloud/tree/master/community-edition is what will most likely be the only way forward.

Consequently, and especially due to a model where Hubs must be self-sovereign and support a governance for its own future, a properly federated solution would help tremendously.

There are on-going efforts like https://github.com/nurse-the-code/hubs-directory/tree/main to list instances but arguably this isn't a scalable solution compared to a properly federated one, like Immers provide.