This adds a very simple Dockerfile and run script for running `act_runner` as a container.
It also allows setting `Privileged` and `ContainerOptions` flags via the new config file when spawning task containers. The combination makes it possible to use Docker-in-Docker (which requires `privileged` mode) as well as pass any other options child Docker containers may require.
For example, if Gitea is running in Docker on the same machine, for the `checkout` action to behave as expected from a task container launched by `act_runner`, it might be necessary to map the hostname via something like:
```
container:
network_mode: bridge
privileged: true
options: --add-host=my.gitea.hostname:host-gateway
```
> NOTE: Description updated to reflect latest code.
> NOTE: Description updated to reflect latest code (again).
Reviewed-on: https://gitea.com/gitea/act_runner/pulls/84
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-by: Jason Song <i@wolfogre.com>
Co-authored-by: Thomas E Lackey <telackey@bozemanpass.com>
Co-committed-by: Thomas E Lackey <telackey@bozemanpass.com>
