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 importlib.metadata import PackageNotFoundError, version
+
+try:
+    __version__ = version("package-name")
+except PackageNotFoundError:
+    # package is not installed
+    pass