SUBMARINE-675. Sync the status of notebook

[lowc1012]

What is this PR for?

1. The notebook REST api will return four states of notebook (creating/waiting/running/terminating) and its reason.

• creating : Users submitted the request to create notebook and its pod haven't been created.
• waiting : Still running the operations it requires in order to complete start up: for example, pulling the container image.
• running : The container is executing without issues and readyReplicas equals to 1
• terminating : Users submitted the request to delete notebook

2. Refactoring K8sSubmitter
3. Update userdocs/k8s/api/notebook.md

What type of PR is it?

[Improvement | Documentation | Refactoring]

Todos

• [@kobe860219 ] - Front-end : Using RxJS to do polling the status of notebook instance and adding spinner when notebook status is creating/waiting.

What is the Jira issue?

SUBMARINE-675

How should this be tested?

Travis CI

Screenshots (if appropriate)

Questions:

• Does the licenses files need update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No

[jiwq]

Why change the service port?

[lowc1012]

Because we deploy Traefik as default ingress controller in Submarine and it exposed with nodePort (32080)

[xunliu]

@lowc1012 Traefik port, can it be fixed?

[lowc1012]

It is fixed for port 32080 if we use 'helm install' command. We can enable submarine expose another port by modified the parameter.

[jiwq]

+1 Will merge if no more comments. Thanks @lowc1012 for the contribution.