Use hatchling and versioningit for versioning

These changes integrate the use of hatchling and versioningit for project versioning, so to add git commit information to the version numbers. Version numbers are now auto-generated from tags or tags+distance as necessary.

src/mednet/__init__.py

+# SPDX-FileCopyrightText: Copyright © 2023 Idiap Research Institute <contact@idiap.ch>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from ._version import version as __version__  # noqa