Docs: improvement of the dubboctl quick start guide

[yin1999]

The steps listed in the dubboctl quick start guide is not corrected. The problems found in testing are as follows:

• The command to init the demo environment is not working:

  dubboctl manifest install --profile=demo

  The command should be changed to dubboctl manifest install --set profile=demo

  A fix is created to resolve the services creation problem: fix(dubboctl): resolve the init logic of k8s environment #290

• Missing the step to create k8s namespace dubbo-demo

• The branch name to dubbo-samples specified in this article is not correct main -> master.

• The command (dubboctl build --dockerfile=./Dockerfile) used to build the application is not correct, it should be replaced with:

  dubboctl build --useDockerfile

• The command used to generate the deploy should specify the namespace: dubboctl deploy --namespace dubbo-demo.

• The port field of the Service resource within kube.yaml file generated by dubboctl deploy is missing (name is missing when generate multiple ports). [fix] fix ci && Dubboctl deploy subcommand error fix #304

• Create CN mirror for releated builders and lifecycle images for buildpacks. feat(dubboctl): add support for using CN mirror of buildpacks toolchain #317

[yin1999]

cross ref: #306, which introduced support for installing dubbo-admin as a k8s service