Workflow cleanup and various fixes

[PathogenDavid]

Merge bonsai-rx/machinelearning-examples#14 before this one.

---

This PR:

• Unifies the build and test GitHub Actions workflows
• Cleans up the GitHub Actions workflows (including fixing PSA: Old versions of actions/setup-dotnet will break soon bonsai#2091)
• Fixes test failures caused by Python 3.1 being used instead of Python 3.10
• Adds building and testing of Linux (via Mono) and the debug configuration
• Removes .NET Standard
  • Projects should either multi-target Framework and modern .NET or target only .NET Standard, not both.
• Targets tests to .NET Framework instead of .NET 8
• Migrates the documentation deployment to use the modern deployment strategy
• Cleaned up and fixed various issues with ReceptiveFieldSimpleCellTest
• Fixes the formatting of the Visual Studio Solution
• Updates the examples repo to fix the documentation workflow (needs Fix malformed Bonsai.configs machinelearning-examples#14)

Supersedes #44

[ncguilbeault]

Everything looks good to me.