Define CI catalog resources and versioning

What does this MR do and why?

Related to Blueprint: Catalog items and version publishing (#373714 - closed)

In this MR we introduce some definitions related to the CI catalog:

• Define what a catalog is.
• Define what a catalog resource is (generic concept).
  • Also define how a pipeline module is a catalog resource.
• Define a pipeline module as a collection of components (the term pipeline module is TBD, I just used a boring term for now).
• Define the versioning of catalog resources.
• Define what the catalog resource page should display, at high level.

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.