docs: upgrade docs from python subscription
docs: support stmt via ws
docs: optimizate python document base on java document

* docs: update csharp connector status

* docs: fix csharp ws bulk pulling

* docs: clarify database param is optional to websocket dsn

* docs: fix java connector mistake

* fix: a few typos

* fix: many typos

* docs: java connector support subscription over websocket

* fix: update 3.0 connector feature matrix

* docs: fix typos and use 3.1.0 in jdbc driver

* fix: update matrix for schemaless java status

* docs: use latest jdbc version in connect section

* docs: refine python connector doc for req_id

* docs: fix tab value and label

* docs: fix tab value and label

* docs: add dbname note in grafa and fix lots of unicode characters in english doc

* docs: support schemaless insert

* docs: code reformat

* docs: this line is inaccurate, in current connector-python repo, it require python >= 3.6.2 because there is a dependence iso8601

* docs: append websocket doc for python connector

* docs: fix tabitem

---------
Co-authored-by: NAdam Ji <jrgwyz@163.com>

* docs: this line is inaccurate, in current connector-python repo, it require python >= 3.6.2 because there is a dependence iso8601

* docs: append websocket doc for python connector

---------
Co-authored-by: NAdam Ji <jrgwyz@163.com>

* test: add python demo for websocket

* fix test

* fix test

* fix test

* docs: update csharp connector status

* docs: fix csharp ws bulk pulling

* docs: clarify database param is optional to websocket dsn

* docs: fix python version and a few typos

* docs: fix jdbc version in connector matrix

* docs: update jdbc demo readme

* docs: update dot-net examples link

* docs: fix example code mistake

* fix: examples/csharp typos

* fix: examples/python/native_insert_example.py mistake

* docs: update python connector document to reflect python version requirement change

* docs: update with two ways to install taos-ws-py

* docs: update csharp connector status

* docs: fix csharp ws bulk pulling

* docs: clarify database param is optional to websocket dsn

* docs: fix python version and a few typos

Missing a quote in the first word

Rephrased sentences, some stylistic changes.

A couple formatting fixes for the Python Connector page.