Make sure manifests folder always exists

[mvazquezc]

If the plan points to a manifests folder that doesn't exist some scripts will fail since the folder won't be copied by the plan.

This PR modifies the scripts relying on the manifests folder so if the folder doesn't exist, it will be created by the scripts.

[karmab]

addressed in https://github.com/karmab/kcli-openshift4-baremetal/commit/8d59176dc3470f8ac8b3ed1868c7e1365758afa5 instead