Code quality/project standards alignment

[woodruffw]

Similar to crytic/slither#2096.

This is a meta-issue, intended to track sub-issues that will align solc-select's codebase, development practices, etc. with the rest of our public tooling.

• Align README.md with our doc practices
• Modernize the Python codebase
  • Switch to pyproject.toml (Switch to pyproject.toml for all project metadata #186)
  • Use pypa/build for the build (sdist and wheel(s))
  • Use ruff?
• Track Python dependency upgrades via dependabot.yml
• Add some kind of QUICKSTART.md or similar guide (broken out from the current README.md)

(This list is not intended to be exhaustive, and will be updated over time!)