Remove runner specific configuration fields from helm in 1.0

With #106 (closed) we deprecated the values in the Helm Chart config which are specific for the GitLab Runner, e.g. 78db9408. See all fields with a DEPRECATED notice above them.

Since users can now specify a config template which accepts all fields we no longer need the deprecated fields.

Example:

values.yaml

runners:
  config: |
    [[runners]]
      [runners.kubernetes]
        image = "ubuntu:18.04"
        privileged = false
        cpu_request = "100m"
        memory_request = "128Mi"

In version 1.0 of the Helm Chart, we should remove these fields so users of the Chart don't get confused needlessly.

---

If you are using a deprecated field, e.g.

helpers:
    cpuLimit: 200m

Go to https://docs.gitlab.com/runner/executors/kubernetes.html and find the field you need to migrate from in case it's not a 100% match. Translating the above deprecated configuration to the new configuration template would be:

values.yaml

runners:
  config: |
    [[runners]]
      [runners.kubernetes]
        image = "ubuntu:18.04"
        privileged = false
        cpu_request = "100m"
        memory_request = "128Mi"
        helper_cpu_request = "200m" # <<<<<