Delete various old config files

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.

(cherry picked from commit 0da89478cc7a5eec7a35bff47e34b824487661a1)

Closes #2449

frontend/.csscomb.json

@@ -1,25 +0,0 @@
-{
-  "remove-empty-rulesets": true,
-  "always-semicolon": true,
-  "color-case": "lower",
-  "block-indent": "  ",
-  "color-shorthand": false,
-  "element-case": "lower",
-  "eof-newline": true,
-  "leading-zero": true,
-  "quotes": "double",
-  "sort-order-fallback": "abc",
-  "space-before-colon": "",
-  "space-after-colon": " ",
-  "space-before-combinator": " ",
-  "space-after-combinator": " ",
-  "space-between-declarations": "\n",
-  "space-before-opening-brace": " ",
-  "space-after-opening-brace": "\n",
-  "space-after-selector-delimiter": " ",
-  "space-before-selector-delimiter": "",
-  "space-before-closing-brace": "\n",
-  "strip-spaces": true,
-  "tab-size": true,
-  "unitless-zero": false
-}

frontend/.jsbeautifyrc

@@ -1,12 +0,0 @@
-{
-  "js": {
-    "indent_size": 2,
-    "indent_char": " ",
-    "indent_level": 2,
-    "indent_with_tabs": false,
-    "preserve_newlines": true,
-    "brace_style": "collapse",
-    "max_preserve_newlines": 2,
-    "jslint_happy": true
-  }
-}