* [TD-4752]<doc>: python connector supports nanoseconds.

* update english document too.

commit 0c81e3c0ba89c86f6d17d51d5056146e177cace5
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Fri May 14 10:27:13 2021 +0800

    [TD-4160]<fix>: remove python connector soft links, fix tests and documents

commit f439fce413423e7d7c97eef180c93d63dedab32e
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Wed May 12 18:50:53 2021 +0800

    [TD-182]: bump python connector version to v2.0.10 (#6091)

    Also fix url error in setup.py

commit 4ae55d494a262e482f6b34e8bf193cc6af62a886
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Wed May 12 09:49:26 2021 +0800

    [TD-4370]<fix>: merge python connector changes to master

    Inludes:

    [TD-182]<enhance>: use single repo for python connector (#6036)

    * [TD-182]<enhance>: use single repo for python connector

    Remove code for each platform and build up one single python code base
    for windows/osx/linux platforms and python2/python3 runtime.

    * [TD-182]<enhance>: remove redundant code in python connector

    * [TD-4149] <fix>: fix python connection config error

change jdbcType and SQLType

TDengine-2.0.18.0 need using taos-jdbcdriver-2.0.22

[TD-2271]<doc>: add Error Code and Message for JDBC-driver,JNI method and TDengineError