Devfile parser library should generate Kube objects

[maysunfaisal]

The devfile/parser library should be able to generate basic Kubernetes objects from the devfile. The list of these functions and objects can be found documented at the design doc for the library and also the util funcs that can be found in the same doc.

Currently, Odo and Devworkspace operator repo generate their own Kube structs and objects, so there is a lot of redundant code and this issue will be solving that problem for all the consumers of the devfile/parser. For example, this google doc outlines the odo and devworkspace operator repo functions for these generator code.

The generated Kube objects are only going to be static objects ie; they would not need cluster communication.

Parent Issue: #144

[maysunfaisal]

I have outlined the work that needs to be done for this issue here in the document - https://docs.google.com/document/d/1ffLi37fM7LAjRK5SXAw-yVNwr9GchFYy_e_5VD-FOZc/edit#heading=h.v1ex47x85625

I have divided them into first pass and second pass; where first pass requires little to no refactoring of Odo code and is of higher priority compared to the second pass.

[yangcao77]

The work in library repo has been done.
The only thing left is to port over the last piece of generator (GetInitContainer) to odo.

[yangcao77]

PR created in Odo: redhat-developer/odo#4809

[yangcao77]

This issue has been done