Enable Additional Docker Run Arguments

[lenaing]

Why this pull request ?

This pull request enable Jenkins adminstrator (or users) to add specific arguments to each docker run commands issued by the plugin to the underlying Docker Pipeline node.

Context

At $daywork, we are migrating from an old DCOS infrastructure, with DIND containers having access to the Docker Socket, to Kubernetes DIND containers (without Docker Socket access).

DCOS DIND containers automatically remount all volumes, including a TLS CA bundle that is provided to the Docker Pipeline Node.
On Kubernetes, the volumes is not found (as there is no volume found for the container exposed through the DIND without a shared socket), so we needed a way to append specific args to each docker run command as such : -v /etc/ssl/certs/tls-ca-bundle.pem:/etc/ssl/certs/tls-ca-bundle.pem:ro,z (The TLS CA bundle is exposed to the DIND container by Kubernetes through a config map).

This enable us to migrate our infrastructure without having to ask our numerous users to append an "args: ..." to all of their pipelines' code.

Testing done

Modified current tests to check for Global and Folder config / overrides.

Currently opened to our internal user base in beta befor pushing to our production infrastructure.

### Submitter checklist
- [x] Make sure you are opening from a **topic/feature/bugfix branch** (right side) and not your main branch!
- [x] Ensure that the pull request title represents the desired changelog entry
- [x] Please describe what you did
- [ ] Link to relevant issues in GitHub or Jira
- [ ] Link to relevant pull requests, esp. upstream and downstream changes
- [x] Ensure you have provided tests - that demonstrates feature works or fixes the issue