Added a first implementation of a new API with fastapi.

.gitignore

.pylintrc

gui/public/env.js

gui/src/config.js

nomad/app/__init__.py

nomad/app/api/common.py

nomad/app/common.py

nomad/app/optimade/api.py

nomad/app_fastapi/main.py

nomad/app_fastapi/models.py

nomad/app_fastapi/routers/auth.py

nomad/app_fastapi/routers/entries.py

nomad/app_fastapi/routers/users.py

nomad/app_fastapi/utils.py

nomad/archive.py

nomad/config.py

nomad/datamodel/datamodel.py

nomad/infrastructure.py

nomad/metainfo/elastic_extension.py

nomad/metainfo/metainfo.py