Adding capability to set zone for bastion

[chrislovecnm]

Added capability to set a zone value for the bastion, because some regions do not have 'a' zone.

• Added new api structure for the bastion
• Updated full.yaml with new api values
• Modified network.tf.tmpl to support api values
• Updated unit test to test changes
• Modified Makefile to use full.yaml
• commented out some values in full.yaml that are project specific

Fixes: https://github.com/GoogleCloudPlatform/gke-terraform-generator/issues/6

[chrislovecnm]

@ludoo PTAL and test drive