By default when you mount a Docker volume to a container it gets the
`755` permissions, meaning that anybody can read from it but users who
aren't root, can't write to it. Before
https://gitlab.com/gitlab-org/gitlab-runner/-/merge_requests/1989 be
used to run
[cache-init](https://gitlab.com/gitlab-org/gitlab-runner/-/blob/25bde74c/commands/helpers/cache_init.go)
on the directory before the volume was created, this is no longer the
case. This breaks a lot of users script that used to write to the
volumes that were mounted, and is a fairly big regression.

Create a new pkg `permission` that handles updating permissions to the
volumes that we create, and make it more explicit that we are updating
the permissions of the volumes, as before it wasn't very clear that it
was being done. The permissions is implemented both for Linux and
Windows, currently the windows one is noop because the goal of this
commit is to fix the regression we never supported this on Windows and
will be tackled in
https://gitlab.com/gitlab-org/gitlab-runner/-/issues/25480.

Add an integration test so that we make sure we never have this issue
anymore.

closes https://gitlab.com/gitlab-org/gitlab-runner/-/issues/25440