Container feature detection

There are an increasing set of features which are:

• not in the spec
• required in practice for all production homeservers.

A few examples:

• ability to delete media.
• ability to delete rooms/history entirely.
• change rate limits for the CS API.

It would be nice if a homeserver could "declare" that it supports this, which then runs some magic command on the container to enable/disable this in the container prior to startup (to avoid needing to SIGHUP a running container or other nonsense). If this declaration API is standardised, it would allow the same rate limit tests to work across different HSes for example, and if not, it can be easily skipped.

This has overlap with https://github.com/matrix-org/complement/issues/654 which suggests a configuration format for saying which tests should be run. One can imagine that the "rate limit tests" were an MSC and hence could be opted-in to. The difference is that this needs configuration on a per-test basis, as we usually want very high rate limits in tests.

Inizia confrontando questa proposta con Complement issue 654, in particolare con il formato di configurazione suggerito. Definisci come un homeserver dichiara il supporto per le funzionalità e come tale dichiarazione abilita o salta i singoli test prima dell’avvio del container. Il lavoro è completato quando l’approccio copre esempi come l’eliminazione dei media, l’eliminazione delle stanze/della cronologia e i limiti di frequenza per test, senza richiedere il riavvio di un container in esecuzione.