[FEATURE] remove static JS includes and rewrite all JS to ES6 modules

Ist jetzt alles so umgeschrieben, dass man im project_theme nur noch 'sgnews' importieren und initialisieren muss. Beim ScrollBrowser müsste man überlegen, ob der nicht eigentlich generell ins Theme gehört.

An sich ist das jetzt auch breaking. Das JS muss ja aktiv importiert werden, im Gegensatz zu früher.

Upgrade.md

+# Upgrade from ```6.x.x``` to ```7.x.x```
+
+In Version 7, we rewrote all included JavaScript to ES6 modules. This means that they won't be included in your site automatically when you install the extension.
+
+## Importing the sgnews bundle in your main project
+
+sg_news offers a front-package that imports all sub modules and initilaizes them correctly. You can import this in your bundle like that:
+
+```js
+import SgNews from 'sgnews';
+new SgNews();
+```
+
+### Mapping ```sgnews``` to the extension JavaScript
+
+In order for your module bundler to find the ```sgnews``` package, you need to add the path to your configuration. If you are using the SGC, you can add the following to your ```.sgc-config.json```
+
+```js
+{
+	"js": {
+		"libraryPaths": [
+			...
+			"./web/typo3conf/ext/sg_news/Resources/Public/JavaScript/"
+		]
+	}
+}
+```