Format code and set-up linter

[owlang]

Developer quality of life issue ticket.

We should do a major formatting commit to adhere to a style guide and set up a linter.

Something like this will allow us to select a style and integrate the linter with gradle to lint the project through a gradle command. This can also integrate into git with a git hook so that it lints files before making a commit (can toggle to only lint files that were changed on a feature branch).

https://medium.com/@anirudhramesh95/enforcing-formatting-standards-for-your-java-project-using-gradle-2c21172743e5