Modernize and streamline python packaging

[bdewilde]

Description

• removes setuptools-based package builds in favor of build
• moves mypy configuration into pyproject.toml
• extends and tidies up repo Makefile
• fixes and streamlines installs during github workflows

Motivation and Context

Python's packaging tooling and recommendations continue to evolve: setuptools has gotten out of the building business, pyproject.toml has added more supported tools, and a couple of PEPs got approved. These changes bring textacy into line with modern but not-too-fancy packaging.

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation, and I have updated it accordingly.