vinyl: cleanup dump/compact info/error log messages
vinyl: cleanup dump/compact info/error log messages

 - Do not print range id and index lsn as they don't make much sense any
   more (don't point to a file), only print range boundaries and space
   and index id.
 - In case of split print the key by which it is done.
 - Remove debug messages for range creation/deletion, because with the
   split key being printed on compaction they are redundant.
 - Also, while we are at cleaning up log messages, let's use say_warn()
   instead of say_info() for notifying the user that the scheduler was
   throttled, because it is rather abnormal.

rtsisyk/tarantool,rtsisyk/tarantool,mejedi/tarantool,mejedi/tarantool,rtsisyk/tarantool,mejedi/tarantool,mejedi/tarantool,rtsisyk/tarantool