Add ability to load CND files specified in json config from file-system on startup

When modeshape is being started from json config file it can load some resources from both file on file-system and resource in classpath (eg. cache config for infinispan).

It is not applicable to "Node-Types" property which handles only classpath resources and blocks us from storing all the configs on file-system.

It can be seen in class NodeTypesImporter:

InputStream cndFileStream = runningState.environment()
.getClassLoader(NodeTypesImporter.class.getClassLoader())                                                   
.getResourceAsStream(cndFile);

which might use modeshape's IoUtil to apply common logic:

ClassLoader classLoader = runningState.environment()
.getClassLoader(NodeTypesImporter.class.getClassLoader());

InputStream cndFileStream = IoUtil.getResourceAsStream(cndFile, classLoader, null);