migrate from catch2v2 to catch2v3 and implement VisorTest helper lib

[leoparente]

Migrate pktvisor tests from Catch2 v2 to Catch2 v3

• Perform the upgrade based on: https://github.com/catchorg/Catch2/blob/devel/docs/migrate-v2-to-v3.md.
  • PS: with that change, no main.cpp is required anymore for tests
• Created LibVisorTest to initialize spdlog whenever it is required using Catch2 v3 standard.
• Reduced folders and files complexity by migrating test cmake commands to Module CmakeFile

[weyrick]

great, thanks for this!