store CRDs in separate files

With !214 (merged) merged, we want to manage how CRDs are stored. Currently. we were storing all the combined CRDs into a single file. But in case of some CRDs which doesn't starts with a --- it poses an issue as two CRDs were being combined into one while concatenating (faced only in case of Gatekeeper CRDs for now).

Ref: kubernetes/magnum!264 (closed)

Parent issue: #94 (closed)