RDF'ed serialization


- added new RDF format with IS_IN_FORMAT relation
- added separate RDFS_LABEL to the RDF format
- pointed object HAS_SERIALIZATION to RDF format
- added getSerializationTitle to bridge HAS_SERIALIZATION -> IS_IN_FORMAT -> RDFS_LABEL gap
- modified unit test
- updated views page

Resolves https://www.pivotaltracker.com/story/show/65221404
These are the lines of hack that this current ticket is designed to remove:
```
final String uri = subject.getURI();
final String target = "fcr:export?format=";
if (uri.contains(target)) {
      // Return the value of the query param "format".
                 return uri.substring(uri.indexOf(target) + target.length());
}
```

See updates that introduced this hack: https://github.com/fcrepo4/fcrepo4/pull/227/files#diff-d2db406e1c0a8996c035d902dbfd0d16R147