```
Serve cfcheckpt messages if basic block filter index is enabled and
-peercfilters is set.
NODE_COMPACT_FILTERS is not signaled to peers, but functionality can be
used for testing and serving pre-configured clients.
```
Backport of core [[https://github.com/bitcoin/bitcoin/pull/18877 | PR18877]].
Depends on D8461 and D8462.