Added icons, helperfunction and new fancy notice message

Added icons from webcrunch resp. heroicons
Added helperfunction to display inline svg with the plugin inline-svg
Implemented fancy notice message webcrunch. Realy nice but does only
work with javascript on.

app/assets/images/icons/outline/rss.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true">
+  <path stroke-linecap="round" stroke-linejoin="round" d="M12.75 19.5v-.75a7.5 7.5 0 00-7.5-7.5H4.5m0-6.75h.75c7.87 0 14.25 6.38 14.25 14.25v.75M6 18.75a.75.75 0 11-1.5 0 .75.75 0 011.5 0z"/>
+</svg>