Support lists in manifests

[viglesiasce]

It is common for Kubernetes users to have folders of manifests that they apply by passing multiple -f flags. For example kubectl apply -f k8s/staging/ -f k8s/services/ .

It is not currently possible to use multiple manifest paths per build step which means configuring multiple build steps in order to accomplish what is usually a single kubectl command.

[avadhut007]

yes we should be able to pass the list of config yamls in manifest option