ANY23-295 Implement ability to use librdfa

This project will implement a new RDFa parser for Apache Any23 through a wrapper of the native C/C++ library Librdfa. The implementation aims to evaluate the level of compatibility between both projects and quantify the performance improvement that a native parser could achieve in Any23. In addition, it is proposed to test the integration results against the rdfa.info test-suit in order to validate the approach. The benefits of implementing a more efficient parser are extremely relevant taking into account that RDFa processing takes place in the web where the amount of data is huge.