Added structure_type, structure_prototype and strukturbericht_designation to EncyclopediaNormalizer.

Added formula and formula_reduced to EncylopediaNormalizer. Cleaned up the function for forming the Hill notation.

Added exception handling when reference from scc to system is missing, added bravais_lattice to Encyclopedia.material.

Modified the metainfo enum class, fixed issues in encyclopedia normalization, fixed error in the retrieval of representative systems.

Added a package level conftest.py for normalizer tests, fixed issue in fcc_crystal_structure.json (cell was given in angstroms, not SI units), added first test configuration for EncyclopediaNormaliser.