[TD-2758]<fix>: database may always in syncing state because a node is offline

[TD-2606]<enhance>: enlarge TSDB_MAX_WAL_SIZE from 2M to 3M

[TD-2752]<fix>: check if the FILE pointer is valid or not.

Update tscSubquery.c

[TD-2756]<fix>: correct docstring in taos.cfg

avoid repeated subtraction of the number of subqueries.

Docs/update documents for Sprint_112

Release/s111

fix char string overflow

Feature/sim

tuning tcp opt

[TD-2516]<fix>:taos crash when receiving meta response while query is canceled

[TD-2657]add max wait time to fix case fail issue

[TD-2738]<fix>: null tag issue when having two autocreate tables in single SQL statement

[TD-2598] feature: C# taosdemo, CI integration.

[TD-2746] <fix>: fix required minimal cmake version in all CMakelists…

[TD-2693]<test>: add test case

Feature/query

[TD-2723]<test>add case for multi-level storage

[TD-2710]<fix>: fix deadlock with batch create table

[TD-2677]<fix>: setting quorum to 2 may cause a deadlock