GitHub Actions update

[rkpamegan]

• Updates Windows server versions to 2022, as 2019 was outdated. Windows 2025 will become the latest server version on September 2, 2025, but Windows 2022 will retain support until 2028 according to this.
  • Also updated the Visual Studio generator to 2022.
• Added a second documentation-building action which builds Sphinx docs on Linux rather than Windows. This is meant to serve as a replacement, but I wanted to make sure it works properly before deleting the previous action.
• Added Linux and Windows tests in separate actions. These will run on push to the dev, dev_stage, or main branches. They perform HFUnitTests, pytest, and Sphinx doctest.
• Added a Makefile for building Sphinx docs in Linux, which comes from cadop/seg1d.
• Small changes to some files. The old versions of these files caused crashes to the Linux and Windows tests mentioned above.