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>

package.json

@@ -53,9 +53,10 @@
     "worker-loader": "2.0.0"
   },
   "devDependencies": {
-    "eslint": "6.8.0",
-    "eslint-config-airbnb-base": "14.1.0",
-    "eslint-plugin-import": "2.20.2",
+    "eslint": "7.2.0",
+    "eslint-plugin-import": "2.21.1",
+    "eslint-plugin-sonarjs": "0.5.0",
+    "eslint-plugin-unicorn": "20.1.0",
     "stylelint": "13.3.3",
     "stylelint-config-standard": "20.0.0",
     "updates": "10.2.11"