Change downstream projects configs to file_config (#1776)
So that the downstream projects use a matching config file at the same
last green commit of the project being tested.
For a few downstream projects, we have their config files in the CI
repo, therefore we need to keep the `http_config` for them.
Also deleted downstream configs for `rules_k8s`, `rules_appengine` and
`Subpar` since they are no longer active.
Addressing
https://github.com/bazelbuild/continuous-integration/issues/1759#issuecomment-1766876380
1 file changed