Prezmanifest

* moved to using schema.org over DCAT for catalogue elements
* still handles now legacy DCAT constructs
* added ISU Catalogue Case Study to README

* update the use of underlying kurra package to 1.x
* enable authenticated SPARQL Endpoint ops
* blacked all code
* Optimized Inputs

* all tests depending on a Fuseki instance are using containerised Fuseki with data files in tests/ only needed

* labeller can updated a given manifest with an additional label resource, if given additional context covering missing labels

* kurra (previsouly kurrawong-python) is now a PyPI-based dependency
* consistent versioning