Currently running from nomad.mkdocs import define_env results in a ModuleNotFoundError: No module named 'fastapi' error due to the imports of the following doc strings:

from nomad.app.v1.models import query_documentation, owner_documentation
from nomad.app.v1.routers.entries import archive_required_documentation

in nomad.mkdocs.__init__.py.

By moving these imports into the only place they are used, the doc_snippet() macro, the define_env can now be imported without the infrastructure dependencies.

Closes #2291 (closed)