Add editorconfig to have uniform settings for every contributors

[bew]

TSIA

Reference: https://editorconfig.org
The file is automatically read by Neovim since a few versions already ✨

This is useful as I personally use 2 spaces for Lua indents, but this project uses tabs exclusively and I had to run :set shiftwidth=2 noexpandtab to avoid making a completely different formatting as the rest of the project.
Now I only have to open a Lua file, and Neovim is automatically configured to use tabs

[L3MON4D3]

Good idea!
I'll bump max_line_length/textwidth to 80, I think that's what I've been using so far and most longer comments adhere to it.
If you're fine with that, I'll merge :)

[bew]

Yes, let's go ;)

[L3MON4D3]

A'ight :)