Pyp2spec

Added
- Added a possibility to create spec files for specific Python versions
Use a new command-line option `-p, --python-alt-version` to set it.

Added
- Automatically detect whether a package is archful or not based on a wheel name.
If so, `BuildArch: noarch` is not used in the resulting spec file.
If so, `BuildRequires: gcc` is automatically added to the resulting spec file.
- Automatically detect the package extras, provided that an extra contains at least one additional requirement
The detected extras are declared as RPM subpackages and required in the build time.

Changed
- Use project version JSON API available at PyPI to obtain package metadata.
This ensures all the fields are relevant for the requested package version

Removed
- CLI `--archful` switch - it's detected automatically now
- `manual_build_requires` config option
- `extra_build_requires` config option
- `extra_tox_env` config option
- support for Python 3.8

Changed
- rpmautospec macros (`%autochangelog` and `%autorelease`) are now used to populate the respective
fields in the generated specfile. The CLI options for defining custom values have been removed
- Convert the Python classifiers to Fedora SPDX expressions (where possible, based on [PEP 639](https://peps.python.org/pep-0639/))
- When `--fedora-compliant` option is set, a check of the converted license expressions is performed
to determine whether the license is allowed in Fedora. Data is provided by the [Fedora Legal team](https://gitlab.com/fedora/legal/fedora-license-data/)
- tomllib library is used to read toml files from Python 3.11 on

Fixed
- pyp2spec quits when a package is not found on PyPI

Fixed
- Include LICENSE-MIT-0 in the sdist and fix license metadata

Changed
- template.spec and the files created by pyp2spec are relicensed under MIT-0 (No attribution) license
- PyPI package names are normalized according to PEP 503 to better conform with [Library naming guidelines](https://docs.fedoraproject.org/en-US/packaging-guidelines/Python/#_naming)
- "Initial package" is the new default changelog message, which better reflects the needs of packagers

Changed
- Clearly state in version that project is in the alpha maturity phase,
its API may be subject of change