Google Cloud Authentication

[otaviof]

Adding import to load GCP authentication libraries. To prevent the following:

[2019-04-12T10:27:34+02:00]  INFO This is Landscaper v1.0.21 commit=df2a7d6a7db7a552576899b9fe8c85fdcc0af973 tag=v1.0.21
[2019-04-12T10:27:34+02:00]  INFO Apply landscape desired state dir= dryRun=true environment= helmHome=/Users/ofernandes/.helm namespace=default releasePrefix=default- verbose=true wait=false waitTimeout=5m0s
[2019-04-12T10:27:34+02:00] DEBUG Setup Kubernetes Client
[2019-04-12T10:27:34+02:00] FATAL Could not build Kubernetes client config error=could not get kubernetes client: No Auth Provider found for name "gcp"

Additionally, making changes in Dep to compile api-machinery without the need of the fix script, adding prune to vendor directory.

[rollulus]

Hey nice, and thanks for cleaning up the ugly script as well!

[otaviof]

@rollulus yw && thanks :-)