Clean up documentation, configuration, and CI following S2 version update

[paleolimbot]

This PR:

• Cleans up the configure script to remove pathways that are no longer supported. Basically, pkg-config is required now (because resolving the linking order of the absl static libraries is absolutely insane without it). It also improves the error messages for various types of failures, although probably not all of them.
• Adds Docker images and a docker compose setup to ensure that the compile + test works based on the install instructions for various linux setups. Notably, it makes sure that it effectively uses system Abseil where available (e.g., debian testing, fedora >= 39, alpine), and that it does not use system Abseil of an insufficient version (e.g., all current Ubuntu, Fedora 36).
• Improves the CI jobs to effectively use system Abseil where possible (basically just MacOS). I added a bit of a "pre-check" job that, if it fails, will prevent the other long-running jobs from kicking off. This should give relatively rapid feedback for the feature development + test cycle (and not significantly delay changes related to the build).

This PR does not fix R 4.0 and R 4.1 on Windows yet (battle for another day).