We saw that in large clusters direct failure detector may cause large task queues to be accumulated. The series address this issue and also moves the code into the correct scheduling group.
Fixes https://github.com/scylladb/scylladb/issues/27142
Backport to all version where 60f1053087 was backported to since it should improve performance in large clusters.
Closesscylladb/scylladb#27387
* github.com:scylladb/scylladb:
direct_failure_detector: run direct failure detector in the gossiper scheduling group
raft: drop invoke_on from the pinger verb handler
direct_failure_detector: pass timeout to direct_fd_ping verb