Move troubleshooting guide into user_guide

[fxue]

Following the instruction for user_guide.md, saw the following error.
I am on google cloud GKE

my-kubeflow ks apply ${KF_ENV} -c kubeflow-core

INFO Updating services kubeflow.k8s-dashboard
INFO Updating services kubeflow.tf-hub-0
INFO Updating services kubeflow.tf-hub-0
INFO Updating clusterrolebindings ambassador
INFO Updating roles kubeflow.jupyter-role
INFO Creating non-existent roles kubeflow.jupyter-role
ERROR Error updating roles kubeflow.jupyter-role: roles.rbac.authorization.k8s.io "jupyter-role" is forbidden: attempt to grant extra privileges: [PolicyRule{Resources:[""], APIGroups:[""], Verbs:[""]}] user=&{blad@blah.com [system:authenticated] map[]} ownerrules=[PolicyRule{Resources:["selfsubjectaccessreviews"], APIGroups:["authorization.k8s.io"], Verbs:["create"]} PolicyRule{NonResourceURLs:["/api" "/api/" "/apis" "/apis/" "/healthz" "/swaggerapi" "/swaggerapi/" "/version"], Verbs:["get"]} PolicyRule{NonResourceURLs:["/swagger-2.0.0.pb-v1"], Verbs:["get"]} PolicyRule{NonResourceURLs:["/swagger.json"], Verbs:["get"]}] ruleResolutionErrors=[]

Saw this change, and followed the following and it worked.
Should we add it back to the doc?

-### Google Kubernetes Engine

-Google Kubernetes Engine is a managed environment for deploying Kubernetes applications powered by Google Cloud.
-If you're using Google Kubernetes Engine, prior to creating the manifests, you must grant your own user the requisite RBAC role to create/edit other RBAC roles.

-commandline -kubectl create clusterrolebinding default-admin --clusterrole=cluster-admin --user=user@gmail.com -

[jlewi]

The relevant information is in the troubleshooting guide in our README.md

The fact that the information is not in our user_guide seems undesirable.

I suggest moving the troubleshooting guide into the user_guide.

On the main page we should update the troubleshooting information to just be a link to the relevant section in the user_guide.

[fxue]

I can take a stab at this.

[fxue]

Pull request out for review.