WIP: Check for expired CACAOs when applying new commits

[stbrody]

Still a WIP. There are some issues to iron out if the genesis commit itself has an expired CACAO, including removing the stream from the index in that case. But this PR is getting complex enough that before I go too much further with it I wanted to get some more eyes on it and see if the general direction seems right.

[linear[bot]]

NET-1728 Check for expired CACAOs when applying new commits

Currently we just blindly apply commits. This is problematic if there are previous commits with expired CACAOs that have expired.

We can fix this by adding expiry times inside of state.log and check for expired previous commits when we apply new ones.

[stbrody]

will put up new PRs for this work, closing this draft