The status page should note the FFI packages are deprecated

In my recent PR sq-user-guide!24 (merged) I was told by @nwalfield that the FFI bindings are deprecated. This is confirmed by this commit which also gives a good justification.

Currently the status page says the C FFI bindings are "Incomplete" & Python are "early prototype". This is misleading.

Ideally, the projects page should also mention this deprecation too (there is no indication on that page right now).

Not documenting this deprecation is a problem for end users, who might end up developing against it and be surprised when it's not maintained.

Also this change is (probably) needed before we ask the Arch maintainers to remove the FFI bindings from the default sequoia group (there is a good chance they will remove it entirely).

I did not make a Merge Request because it seems like a team-member/collaborator should do it (I have only ever contributed 3 lines to docs 😉 )