Add swift 4.2 runtime support to default deployments

[csantanapr]

Title: Add swift:4.2 runtime support to default deployments

1. Add swift:4.2 to core ansible/vagrant deploy

• Add swift:4.2entry into ansible/files/runtimes.json
• Update and add doc file into docs/actions.md
• Update unicode tests https://github.com/apache/incubator-openwhisk/tree/master/tests/dat/actions/unicode.tests
• Update swagger file https://github.com/apache/incubator-openwhisk/blob/master/core/controller/src/main/resources/apiv1swagger.json

3. Add swift:4.2 to docker-compose deploy

• Add swift:4.2 into runtime manifest
  https://github.com/apache/incubator-openwhisk-devtools/blob/master/docker-compose/docker-whisk-controller.env#L64

4. Add swift:4.2 to deploy-kube

• Add nswift:4.2 into runtime manifest
  https://github.com/apache/incubator-openwhisk-deploy-kube/blob/master/helm/openwhisk/runtimes.json

5. Update wskdeploy with swift:4.2

• Update spec, and tests for swift:4.2
  https://github.com/apache/incubator-openwhisk-wskdeploy/blob/master/runtimes/runtimes.go#L267
  https://github.com/apache/incubator-openwhisk-wskdeploy/blob/master/specification/html/spec_actions.md#valid-runtime-names
  https://github.com/apache/incubator-openwhisk-wskdeploy/blob/master/tests/src/integration/runtimetests/manifest.yaml#L5

6 Update website with swift:4.2

• Update js action section with swift:4.2
  https://github.com/apache/incubator-openwhisk-website/blob/master/_layouts/documentation.html
  https://github.com/apache/incubator-openwhisk-website/tree/master/_includes/code