* restore .gitmodules for 2.0

* Revert "[TD-13408]<test>: move tests out from TDengine"

This reverts commit 9d342bf3f5b404fc1014400060e012b387bfdb8c.

* immigarate file change from stand-alone repo to TDengine

for 2.0

* remove tests repository checkout
Co-authored-by: Ntangfangzhi <fztang@taosdata.com>

* [TD-13408]<test>: move tests out from TDengine

for 2.0

* add Jenkinsfile2
Co-authored-by: Ntangfangzhi <fztang@taosdata.com>

* [TD-3880]<fix>: C# driver test miss unsigned type.

* [TD-3880]<fix>: C# driver test miss unsigned type.

also modify other files as what  TD-3204 did.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-3877]<fix>: C# query result determination mechanism changed.

* [TD-3877]<fix>: C# query result determination mechanism changed.

change taosdemo and C#checker.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

update README.md

support multithread create table and insertion.