Allow running E2E tests before approval with a manual job

.gitlab/ci/build-images.gitlab-ci.yml

.gitlab/ci/frontend.gitlab-ci.yml

.gitlab/ci/qa.gitlab-ci.yml

.gitlab/ci/rules.gitlab-ci.yml

.gitlab/ci/setup.gitlab-ci.yml

danger/qa_selector/Dangerfile

scripts/generate-message-to-run-e2e-pipeline.rb

spec/dot_gitlab_ci/rules_spec.rb

spec/scripts/generate_message_to_run_e2e_pipeline_spec.rb

spec/tooling/danger/stable_branch_spec.rb