feat: reference ConfigMaps in envs and volumes sections in config

[zroubalik]

Signed-off-by: Zbynek Roubalik zroubali@redhat.com

Follow up on #369, users can reference Kubernetes ConfigMaps in the func.yaml, in envs and volumes sections the same way it is done for Secrets, see the example:

name: test
namespace: ""
runtime: go
...
volumes:
- configMap: mycm3
  path: /workspace/configmap
envs:
- name: EXAMPLE1
  value: myvalue
- name: EXAMPLE2
  value: '{{ env.LOCAL_ENV_VALUE }}'
- name: EXAMPLE3
  value: '{{ configMap.mycm2.EXAMPLE3 }}'
- value: '{{ configMap.mycm }}'

Relates: #362