Ensure networkpolicies match pod labels

Feature Request

Reposync PR for this Issue: https://github.com/DoD-Platform-One/gitlab-runner/pull/6

Why

This change updates the NetworkPolicy resources to match the deployed gitlab runner pods using their full name instead of the hard-coded app: gitlab-runner label.

Reasoning behind the change: Matching on the fullname allows the chart to be used to simultaneously deploy multiple instances of the Gitlab Runner.

Proposed Solution

!211 (merged)