ELG API for Northern Sami grammar checker

ELG compatible Flask based API for Northern Sami grammar checker.

Based on 1) lang-sme Finite state and Constraint Grammar based analysers and proofing tools, and language resources for the Northern Sami language with GPL-3.0 License, for which original authors are from GiellaLT and 2) libdivvun, a library for handling Finite-State Morphology and Constraint Grammar based NLP tools in GiellaLT. The tools are used for tokenisation, normalisation, grammar-checking and correction, and other NLP tasks. GPL-3.0 License.