Add prettier and eslint (#831)

* Ignores archived samples
* Uses eslint/recommended rules
* Runs prettier and eslint (including --fix) pre-commit via husky
* Adds new npm scripts: 'lint', 'lint:fix' and 'prettier'
* Does not lint inline js code
* Fix all prettier and eslint errors
* Add custom prettier rules
* Apply custom prettier rules
* Update readme to explain how to setup the repo
* addressed comments

functional-samples/sample.page-redder/manifest.json

@@ -4,10 +4,7 @@
   "manifest_version": 3,
   "version": "0.1",
   "description": "Turns the page red when you click the icon",
-  "permissions": [
-    "activeTab",
-    "scripting"
-  ],
+  "permissions": ["activeTab", "scripting"],
   "background": {
     "service_worker": "background.js"
   }