Consolidate YAML files [part-2] (#9236)

Changes that will help upcoming consolidation work:

- Add variable `githubWebsiteRaw` to config.toml to facilitate building
  links to raw YAML files
- Revise `codenew` shortcode to generate links to raw YAML files instead
  of github.com file view;
- Rename `artifacts` directory to `examples` to better reflect its usage;

Accompanied changes as show cases:

- Moved `deployment.yaml`, `deployment-update.yaml` and
  `deployment-scale.yaml` to the new `examples/application` subdirectory;
- Removed duplicate instances of the above YAML files in other
  directories;
- Update example_test.go to test the relocated YAML files and removed
  testing for files that no longer needed.

config.toml

@@ -55,6 +55,7 @@ deprecated = false
 currentUrl = "https://kubernetes.io/docs/home/"
 nextUrl = "http://kubernetes-io-vnext-staging.netlify.com/"
 githubWebsiteRepo = "github.com/kubernetes/website"
+githubWebsiteRaw = "raw.githubusercontent.com/kubernetes/website"
 
 [[params.versions]]
 fullversion = "v1.10.3"