Add support for Shapes Constraint Language (SHACL) for Eclipse RDF4J

Shapes Constraint Language (SHACL) is a data modelling language which is used to validate RDF graphs against a set of conditions.those conditions are represented as shapes and different other constructs in an RDF graph.The purpose of this project is to add support for Shapes Constraint language in Eclipse RDF4J.This new feature gives the users the ability to describe and constrain the content of RDF graphs using SHACL.Data against the shapes are validated inside the SHACL feature for example, if an input shape does not match with existing rules then it will be indicated.Shape validation process is optimised and tested using suitable test-cases to get the highest performance.

This feature is a minimum useful subset of SHACL and it gives support to the shapes constraint language inside RDF4j framework.It will be built in accordance with W3C(World Wide Web Consortium) Recommendations and Eclipse Distribution License.