Modify http://docs.getcloudify.org/4.2.0/intro/getting-started/ link

[obriensystems]

Getting started on cloudify community edition - via https://wiki.onap.org/display/DW/ONAP+Kubernetes+on+Cloudify

Navigation in the readme links to a missing link - will try to edit
https://github.com/cloudify-cosmo/docs.getcloudify.org/edit/4.2.0-build/content//intro/what-is-cloudify.md#