register-runners: adjust to be more flexible

Instead of hardcoding 2 runners to be registered, you can add profiles
to a directory to specify what runners should be registered.
7 jobs for remove-docker-compose in 6 minutes and 27 seconds (queued for 1 second)
Status Job ID Name Coverage
  Verify
passed #33977
lint

00:00:26

 
  Build
passed #33982
docker-alpine ci-docker-image aarch64
build-aarch64

00:00:20

passed #33983
docker-alpine ci-docker-image armv7
build-armv7

00:00:23

passed #33981
docker-alpine ci-docker-image ppc64le
build-ppc64le

00:06:00

passed #33978
docker-alpine ci-docker-image s390x
build-s390x

00:00:21

passed #33980
docker-alpine ci-docker-image x86
build-x86

00:00:17

passed #33979
docker-alpine ci-docker-image x86_64
build-x86_64

00:00:18