editorconfig file, to maintain consistent formatting

[RoguedBear]

for what does it do, see: https://editorconfig.org/

tl;dr: a specification respected by almost all formatting tools and code editors to maintain a consistent code formatting no matter which code writing tool you are using

should prevent vscode from mucking up existing code's spacing/formatting

kinda kinda #5 (but doesn't close it entirely)

[RoguedBear]

suggested: one more commit where prettier is run on all files so formatting changes can be sourced back to here