Add a child pipeline to run end-to-end tests in master and MR pipelines on GDK

Proposal

As part of gitlab-org/quality/quality-engineering&4 (closed) we intend to run end-to-end (QA) tests on GDK in MRs and in master pipelines.

This issue is for adding a child pipeline achieve that. It depends on gitlab-development-kit#1605 (closed) for the docker image to use in the CI jobs, but the work can proceed in parallel based on the PoC in !91160 (closed).