initial Kubernetes object generation piece to unblock openshift/console

[yangcao77]

Currently openshift/console is looking for common library from devfile/parser to generate a few Kubernetes objects

The issue is to

1. Set up the initial struct of Kubernetes object generation in devfile/parser repo
2. Create the 5 functions required by https://github.com/reginapizza/console/blob/addDevfile/pkg/server/devfile-handler.go#L34, to unblock their work

This issue does not include all kubernetes object generation work, which will be tracked by #181

[elsony]

@andrewballantyne @christianvogt You can use this item to track the devfile services common library work that the dev console needs for the devfile support.

[yangcao77]

We are currently working on refactoring the generator code in odo, which contains functions dev console would need.
This is the PR to track, and it's currently under review: redhat-developer/odo#4134
Feel free to put PR review and suggestion in comments in the above PR.

After that PR got merged, we will simply copy over the generator pkg to devfile/library