Add unit tests for deployment pkg Pull func

[sebrandon1]

Builds on top of #261

Proof of concept PR for adding unit tests wrapping some of the deployment package starting with the Pull func.

Notable changes:

• Added func GetTestClients which helps build a test client for doing unit testing.
• Changed settings.K8sClient to use the Interface instead of the client.
• Changed settings.NetworkingV1Client to settings.NetworkingV1Inteface.
• Vendor changes come from using the fake k8s client and the additional code needed for that as well as the stretchr/testify library.
• Changes v1 to appsv1 similar to #239

[sebrandon1]

Once #273 merges I'll rebase this PR on top of the changes there.