Automatically find `.clang-tidy`; add collapsible section for notes; automatically download artefacts

[ZedThree]

Adds a few small features:

• Try to automatically find a .clang-tidy file
• Make --config_file work with clang-tidy < 12
• Hide long notes in a collapsible section
• Add upload action to make uploading files a bit easier
• Automatically download artefacts from review Action in post Action

Closes #29 Closes #42 Closes #55 Closes #59 Closes #61