Perform offstrategy compaction via the REST API with
a new `keyspace_offstrategy_compaction` option.
This is useful for performing offstrategy compaction
post repair, after repairing all token ranges.
Otherwise, offstrategy compaction will only be
auto-triggered after a 5 minutes idle timeout.
Like major compaction, the api call returns the offstrategy
compaction task future, so it's waited on.
The `long` result counts the number of tables that required
offstrategy compaction.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
f6431824a7