Merge 'perform_cleanup: wait until all candidates are cleaned up' fro…

…m Benny Halevy

cleanup_compaction should resolve only after all
sstables that require cleanup are cleaned up.

Since it is possible that some of them are in staging
and therefore cannot be cleaned up, retry once a second
until they become eligible.

Timeout if there is no progress within 5 minutes
to prevent hanging due to view building bug.

\Fixes scylladb#9559

\Closes scylladb#13812

* github.com:scylladb/scylladb:
  table: signal compaction_manager when staging sstables become eligible for cleanup
  compaction_manager: perform_cleanup: wait until all candidates are cleaned up
  compaction_manager: perform_cleanup: perform_offstrategy if needed
  compaction_manager: perform_cleanup: update_sstables_cleanup_state in advance
  sstable_set: add for_each_sstable_gently* helpers

(cherry picked from commit 3b424e3)