Complete rewrite to add likes

This commit replaces the icon with a SVG and adds the possibility
to like pages too. To do this the whole structure was rewritten
which makes it in the future easier to add new functions.

button.js

@@ -0,0 +1,11 @@
+async function buttonClicked(e) {
+    const [tab] = await browser.tabs.query({currentWindow: true, active:true});
+
+    browser.tabs.create({
+        url: e.target.parentNode.dataset.href + tab.url
+    });
+
+    window.close()
+}
+
+document.addEventListener("click", buttonClicked)