Convert manifest model into a request model

[ibaldin]

Need to be able to take manifest of a slice and turn it into a request (assuming some number of modifications that lead to the latest manifest).

There are at least two ways of achieving that

1. Writing a ManifestParser class that generates a new Jena model that is the request based on parsing the manifest. Mostly straightforward, except, perhaps, for dealing with inter-domain links
2. Copying the manifest model and directly manipulating it using inference and queries to transform it into a request. More interesting from semantic perspective.

Need to decide how to proceed.

@YufengXin