Add .editorconfig to the project

[Cloudef]

Usually C/C++ projects use spaces, so this should override people's space settings assuming they have editorconfig compatible editor or plugin installed.

[Ancurio]

Which IDE is this for?

[Cloudef]

I used this with vim myself. Editorconfig is available widely for all sorts of editors. https://editorconfig.org/

[carstene1ns]

Might want to add some files with specific settings (markdown for example)

[Ancurio]

Accidentally commented from 2nd account, oops :^)

Edit: Original message read: I'm not sure the indent-size is needed since tabs can be changed to be arbitrarily long, but otherwise lgtm. I want to point out that tabs are only for scope-level indentation; aligning multiple lines within the same scope should still be done via spaces.