test: add test cases for trans

Made some grammar and reworded the differences between connectors.

Made grammar changes to the Data Model page.

docs: remove useful parts in 3.0 doc

docs: remove broken link

 fix: avoid memory leak in mnode sync

test: add test cases of tmq

fix: avoid memory leak in mnode sync

fix(query): set the correct schema version for each record in buffer.

fix: avoid memory leak

refactor: sync integrate into mnode

docs: stylistic and phrasing changes

Seems like previous PR was overwritten and reverted to original.

enh: add debug log of tsdb load block data cols

Merge branch 'feature/sync-mnode-integration' of https://github.com/taosdata/TDengine into feature/sync-mnode-integration

fix: follower processes the trans but does not send the action msg

fix: avoid multi thread read/write crash

feat:add json function