rework eslint config (#11615)

* rework eslint config

- use explicit config that only enables rules
- upgrade eslint to 7.1.0
- add new plugins with selected rules enabled
- fix discovered issues, remove global wipPrefixes

* remove if

* undo template change

* add disabled rules as well for easier config updating

* add missing disabled rule

* update eslint and plugins

* fix new violation

* remove deprecated rules

Co-authored-by: Lauris BH <lauris@nix.lv>

web_src/js/features/codeeditor.js

@@ -6,7 +6,7 @@ const languagesByExt = {};
 function getEditorconfig(input) {
   try {
     return JSON.parse(input.dataset.editorconfig);
-  } catch (_err) {
+  } catch {
     return null;
   }
 }