Refactor single file use and add tooling

[pythoninthegrass]

Hi @VikParuchuri!

Thanks for making this! Added some general quality-of-life features/docs and light edits to the convert_single.py script to get it in line with python conventions (e.g., main() vs magic/dunder method call).

Probably missed some stuff in subdirectories and won't be offended if you only use some of the below.

CHANGELOG

• all scripts in top-level directory: chmod +x
• convert_single.py: shebang, sort imports (comment out unused settings import), move argparse to global scope, break out main function from magic method call
• .gitignore: add Brewfile.lock.json exclusion
• .vscode: configure python debugging w/boilerplate args, general python editor settings
• README.md: replace generic brew requirements file w/semantic Brewfile and instructions; minimal shell scripting to get tessdata directory on mac; auto newline at EOF (unix requirement)
• Brewfile: requirements file to programmatically install brew formulae