Chore: minor optimizations

[johannschopplich]

Absolutely stunning plugin! Especially useful, since I'm nowadays using Kirby as headless CMS most of the time.

I've made some minor improvements:

• Use null-coalescing operators of PHP 8 (like Kirby in 3.8+)
• PHP DocBlock comments are not needed anymore, since they are inferred from inline types.
• Added .editorconfig to trim trailing whitespace (was in one of your function titles)
• Added .gitattributes to exclude folders like .github from the generated ZIP file packed by Packagist and downloaded by Composer

Hope you like those minor improvements.

[johannschopplich]

Especially the title screen. Beautiful!

[tobimori]

Thank you! :)