Document alternative deploy method of Kubeflow Pipelines (kubeflow#1174

)

* initial

* Document alternative deploy method of Kubeflow Pipelines

* adjust wording

* Adjust wording to give more context of choices user have

* Change kubectl apply -k to use github url, make it easier to understand where the manifest is

* Improvements based on Sarah's review

* Update KFP lite branding to KFP standalone

* Update to make the doc GCP specific

* Update gcp create cluster guide

* Rename deployment-alternatives doc to standalone deployment gcp

* Address review comments

* Update standalone-deployment-gcp.md