Add Lua linter to github actions

[timothymtorres]

Features

• Adds Lua linter to Github Actions for all pull requests and any pushes to master branch

Fixes

• Remove dead trailing whitespace
• Remove unused variables that were reassiged
• Fix line length to be the default 120
• Fix scope of global variables to be local
• Remove unused testing variables
• Refactor function names for clarity

This pull request adds a linter that catches some common mistakes and enforces a max character of 120 per line. (python has 80 chars) A lot of the settings can be toggled or ignored but I think it is a good baseline to use for any Lua project without causing too much hassle.