Fine-grained config for containers/services (privileged, volume mounts)

We need to run service in privileged container (we want to use image gentics/tmpfs-mysql for our integration tests).

Also other options to configure services similarly to runner container can be useful (mount volumes).

Proposed changes

#238 (comment 2449603):

a) use privileged config value of runner.docker also for services

b) add new config value privileged_sevices which will define what services can run as privileged

privileged_services = ["*", "*/*"]

c) add config for services. I'm not sure how exactly this can be implemented.

Maybe new config section in config.toml:

[[runners]]
  url = "..."
  token = "..."
  name = "..."
  executor = "docker"
  [runners.docker]
    image = "..."
    privileged = true
    volumes = ["/workspace/composer-cache:/root/.composer/cache"]
    allowed_images = ["*", "*/*", "*/*/*"]
    allowed_services = ["*", "*/*"]

[[services]]
  [services.mysql/*]
    privileged = true
    volumes = ["/ramdisk:/var/lib/mysql"]