[POC] [PCM] Allow automatic loading from bundles

This PR adds support for automatically loading node type definitions from bundles, just like doctrine schemas.

- The node type files must be located in `Resources/config/phpcr-node-types`
- There is no bundle white / black list, if the folder exists and it contains node types, then they are loaded for *all* registered bundles

I don't *think* its a problem if we always load all node types from all registered bundles, after all, each node type file should be using its own namespace.

This PR builds uses https://github.com/phpcr/phpcr-utils/pull/108