Implement CI Components spec, args and fabricate interpolation context

What does this MR do and why?

This merge request is an attempt to implement domain classes representing a component's inputs specification, user-provided arguments, and fabrication of interpolation context.

Example:

spec:
  inputs:
    stage:
    env:
      options:
        - prod
        - test
        - dev

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.