Multi-manifest Support

[lander2k2]

Currently the gener8s go command only supports a single manifest in a YAML document. This issue is to propose allowing multiple manifests which will produce multiple objects generated in output.

For example:

# +gener8s:var:sampleNamespace
apiVersion: v1
kind: Namespace
metadata:
  name: go-web3-sample-app
---
# +gener8s:var:sampleConfig
apiVersion: v1
kind: ConfigMap
metadata:
  name: go-web3-sample-app-config
  namespace: go-web3-sample-app
data:
  RPCENDPOINT: http://forward-proxy.forward-proxy-system.svc.cluster.local

Included here are markers that allow the variable name to be specified for each object. Order of priority would be:

• object name supplied in marker
• variable name supplied by -v flag (used for all objects without a marker)
• default variable name: resourceObj

In the case that a var name is passed with -v flag and a marker is supplied, we can emit a warning that informs the user that the marker var name will be used.

[lander2k2]

This will be divided into 2 steps:

1. Implement multi-manifest support with generic variable names. The variable name should be different - appending an incrementing int will be sufficient.
2. Move the markers package out of operator-builder into its own project, then import the new library and implement the variable name marker option. Issue: Move markers package to its own project and import it operator-builder#67