build: switch to pyproject.toml

[afuetterer]

Hi, since you merged my PR about the gha setup, I thought I might submit another one.

This modernizes the project setup using a pyproject.toml file.

What do you think?

Refs:

• https://packaging.python.org/en/latest/guides/writing-pyproject-toml/
• https://setuptools.pypa.io/en/latest/userguide/pyproject_config.html

Tasks

• Rebase
• Drop pyyaml from dependencies
• set requires-python to >= 3.10
• add 3.10-3.14 to trove classifiers
• add 3.10-3.14 ci tests
• check if license can be included without manifest file
• squash commits
• update coveralls and pytest-cov dependency (updated previously in requirements.txt)
• waiting for fix: replace urlretrieve in getRemoteFile #444 to be merged, so that CI can (hopefully) pass
• rebase
• squash commits
• add parallel coverage completion job
• squash commits

[chrismattmann]

If this PR looks good to you, I will squash all those tiny commits.

LGTM please squash.

[coveralls]

coverage: 55.646% (+2.2%) from 53.469%
when pulling 66aae33 on afuetterer:toml
into ce4c3ca on chrismattmann:master.

[afuetterer]

Failing test case due to network reasons.