package/gitlab-runner: new package

We rely on config.toml to be created manually during first boot as
setup stage. Even with an empty config.toml file, the gitlab-runner
needs gitlab registration token to register to a gitlab server.

Use the 14.5.1 release since 14.5.2 and 14.6.0 triggers a build error [1]
due a patch for GO < 1.17.
(helpers/patches/issue_28732/syscall.go:11:2: undefined: syscall.Issue28732Fix)

Tested:
https://gitlab.com/kubu93/buildroot/-/pipelines/442604876

[1] https://gitlab.com/gitlab-org/gitlab-runner/-/issues/28766



Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Signed-off-by: Romain Naour <romain.naour@smile.fr>
Cc: Jérémy Rosen <jeremy.rosen@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>