[VS Code] Submit job v2 support

[yiyione]

Support:

• Create job v2 config file in PAI CLUSTER EXPLORER.
• Submit yaml config file.
• Right click yaml/yml file to submit job.

Don't have:

• YAML job config file verification.
• Simulate v2 job running.
• Friendly error message.
• Document.

[coveralls]

Coverage increased (+0.01%) to 53.228% when pulling 3c4f31d on yiyi/vscode_support_yaml into 24e41fa on master.

[coveralls]

Coverage increased (+0.01%) to 53.228% when pulling db091e7 on yiyi/vscode_support_yaml into 24e41fa on master.

[sunqinzheng]

Please use yarn instead of npm.
Yarn uses yarn.lock as version lock file instead of npm's package-lock.json

[sunqinzheng]

Please use yarn instead of npm.
Yarn uses yarn.lock as version lock file instead of npm's package-lock.json

Please remove contrib/pai_vscode/package-lock.json...