fix: return dropping dnode in status resp

fix: no core file generated issue on linux

 enh: vote for higher lastLogTerm despite commitIndex

enh: read mnode file

* fix: add test cases;

* fix(query): fix error for retrieve data only in last files.

enh: add version for show cluster

fix: error code not returned issue

fix:table name error in schemaless

enh: refact raft store file read write

fix: rename global variables

fix: use pInfo->info.state.committed for WAL snapshot instead of the current one for async vnodeCommit

enh: vnodeCommit on consensus only

fix(query): do not merge rows in last file when no data blocks exist.