crit: fix compatibility with Python 3.12

Python 3.12 includes a few breaking changes, such as the removal of the
distutils module [1] and the deprecation of `setup.py install` in
favour of pip install [2]. This patch updates the installation script
for crit to reflect these changes by replacing the use of
`setup.py install` with `pip install` and `distutils` with
`setuptools`. In addition, a minimal pyproject.toml file has
been added as it is required by the new version of pip [3].

It is worth noting that with this change we are switching from the egg
packaging format to wheel [4] and add pip as a build dependency.

[1] https://www.python.org/downloads/release/python-3120a2/
[2] https://github.com/pypa/setuptools/pull/2824
[3] https://pip.pypa.io/en/stable/reference/build-system/pyproject-toml/
[4] https://packaging.python.org/en/latest/discussions/wheel-vs-egg/

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

crit/.gitignore

@@ -0,0 +1,2 @@
+crit.egg-info/
+build/

crit/pyproject.toml

@@ -0,0 +1,2 @@
+[build-system]
+requires = ["setuptools"]

crit/setup.py

@@ -0,0 +1,29 @@
+import os
+from setuptools import setup, find_packages
+
+
+def get_version():
+    version = '0.0.1'
+    env = os.environ
+    if 'CRIU_VERSION_MAJOR' in env and 'CRIU_VERSION_MINOR' in env:
+        version = '{}.{}'.format(
+            env['CRIU_VERSION_MAJOR'],
+            env['CRIU_VERSION_MINOR']
+        )
+        if 'CRIU_VERSION_SUBLEVEL' in env and env['CRIU_VERSION_SUBLEVEL']:
+            version += '.' + env['CRIU_VERSION_SUBLEVEL']
+    return version
+
+
+setup(
+    name='crit',
+    version=get_version(),
+    description='CRiu Image Tool',
+    author='CRIU team',
+    author_email='criu@openvz.org',
+    license='GPLv2',
+    url='https://github.com/checkpoint-restore/criu',
+    packages=find_packages('.'),
+    scripts=['crit'],
+    install_requires=[],
+)