Backend: Make ciCatalogResource accept a fullpath argument

Summary

To allow the new routing for ci catalog resources to be a fullpath instead of a GID, we should also make the graphql file ciCatalogResource accept only the fullpath as an argument. This will require to sync with the client to make sure we don't break existing queries, but it will allow us to have routes like explore/catalog/gitlab.org/rubystuff

Proposal

Add fullpath as an argument instead of GID.

Ensure an appropriate error message is returned when:

• The path is invalid
• The project is not a catalog resource
• Neither id or full_path argument is provided
• Both id and full_path is provided (we want the user to use one argument)

Additional details

Some relevant technical details, if applicable, such as:

• Does this need a feature flag?
• Does there need to be an associated instrumentation issue created related to this work?
• Is there an example response showing the data structure that should be returned (new endpoints only)?
• What permissions should be used?
• Is this EE or CE?
  • EE
  • CE
• Additional comments:

Implementation Table

MR resolving this issue.

Group	Issue Link
backend	👈 You are here
backend	Backend: Support fetching versioned README for ... (#429279 - closed)
frontend	Frontend: Make Catalog resource ID become the f... (#428949 - closed)

Links/References