Conversation containers FEP update

https://codeberg.org/silverpill/feps/src/branch/main/171b/fep-171b.md

It now includes a comparison with other proposals: FEP-1b12 and GoToSocial Interaction Policy.

I think FEP-1b12 and conversation containers can be made compatible, but GtS solution seems to be fundamentally different because conversations there don't have a single "context" managed by OP. Instead, every reply creates a new independent context (doc).

Both approaches have downsides, so it is hard to choose one over the other. I don't like how audience can't be changed in a contained conversation, but I'm still slightly in favor of that solution because it is more efficient and keeps conversations synchronized across servers.

#conversationcontainers