Add Lean testing framework

[mpenciak]

This PR sets up a rudimentary testing framework for the Lean part of the code and closes #34.

• Removes the Lampe.Basic file and moves it to the top-level Lampe.lean
  • The PR also adds all of the library files to Lampe.lean
  • This can be done automatically with lake exe mk_all --lib Lampe
• Adds a Tests library
• Adds a test driver to the lakefile, tests can be executed using lake test
  • Currently the Test is just "Does this module compile?"
  • It can be made more complicated using #guard_msgs commands or more complicated testing
    frameworks
• Updates CI to perform these checks.

Also included is a little cleanup of the lakefile.lean.