Delete `jsconfig.json`
This file actually did nothing since we have a `tsconfig.json`. Behavior does not change since `checkJs` is `false` in both.
Delete `.jsbeautifyrc`
Was not used from what I could tell and we have a ESFormatter config file as well and that is basically the successor.
Delete `.csscomb.json`
Was not used from what I could tell, also the project seems dead, last publish 4 years ago. Also we have stylelint in place that covers CSS.