Setting `fail-fast: false` unsurprisingly makes our CI fail pretty
slowly. This is especially noticable in the merge queue where a
long-running job could still hold up the entire queue even though a
different job has failed already and the PR is never going to make it in
anyway.
To avoid this scenario, we set `fail-fast: true` whenever we are in the
merge queue.
Right now, draft releases for Gateways and headless-clients are created
on each merge to main. For all other components, we only create those
when we trigger the workflow for a specific commit.
To align this functionality, we split the `_build_artifacts.yml`
workflow into two:
- `_control-plane.yml`
- `_data-plane.yml`
Apart from the `sha` input, all inputs only concern the data-plane,
therefore massively simplifying the control-plane workflow.
Additionally, the control-plane also doesn't have a manual trigger
because its artifacts never get released on GitHub.
Resolves: #10541
