[type: feat] Support PostgreSQL && update Readme in English

[aFlyBird0]

Description

• Support PostgreSQL
• Update Readme in English
• Fix websocket error( the namespace in websocket url is hardcoded to shenyu in the past)

Note

Now, there is something wrong with the official image 2.5.0 version about pg. You could use my dockerhub image to test.(executed by make build-all-image, based on 115e33accc, yunlongn yunlongn@outlook.com, Thu Sep 29 17:09:49 2022 +0800)

helm install shenyu0930 bird-shenyu/shenyu -n=shenyu --create-namespace \
      --set version=latest \
      --set admin.image=aflybird0/shenyu-admin \
      --set bootstrap.image=aflybird0/shenyu-bootstrap \
      --set dataSource.active=pg \
      --set dataSource.pg.ip=127.0.0.1 \
      --set dataSource.pg.port=5432 \
      --set dataSource.pg.username=postgres \
      --set dataSource.pg.password=123456

Tested in Ubuntu 20.04

[erdengk]

I think this pr can be merged now, what do you think? @JooKS-me