Fix favicons (#2027)

Author: reakaleek

src/Elastic.Documentation.Site/Layout/_Favicon.cshtml

@@ -1,20 +1,4 @@
-<link rel="apple-touch-icon" sizes="57x57" href="https://elastic.co/apple-icon-57x57.png"/>
-<link rel="apple-touch-icon" sizes="60x60" href="https://elastic.co/apple-icon-60x60.png"/>
-<link rel="apple-touch-icon" sizes="72x72" href="https://elastic.co/apple-icon-72x72.png"/>
-<link rel="apple-touch-icon" sizes="76x76" href="https://elastic.co/apple-icon-76x76.png"/>
-<link rel="apple-touch-icon" sizes="114x114" href="https://elastic.co/apple-icon-114x114.png"/>
-<link rel="apple-touch-icon" sizes="120x120" href="https://elastic.co/apple-icon-120x120.png"/>
-<link rel="apple-touch-icon" sizes="144x144" href="https://elastic.co/apple-icon-144x144.png"/>
-<link rel="apple-touch-icon" sizes="152x152" href="https://elastic.co/apple-icon-152x152.png"/>
-<link rel="apple-touch-icon" sizes="180x180" href="https://elastic.co/apple-icon-180x180.png"/>
-<link rel="apple-touch-icon" sizes="192x192" href="https://elastic.co/apple-icon-192x192.png"/>
-<link rel="icon" type="image/png" href="https://elastic.co/favicon-32x32.png" sizes="32x32"/>
-<link rel="shortcut icon" href="https://elastic.co/favicon.ico" type="image/x-icon"/>
-<link rel="icon" href="https://elastic.co/favicon.ico" type="image/x-icon"/>
-<link rel="apple-touch-icon-precomposed" sizes="64x64" href="https://elastic.co/favicon_64x64_16bit.png"/>
-<link rel="apple-touch-icon-precomposed" sizes="32x32" href="https://elastic.co/favicon_32x32.png"/>
-<link rel="apple-touch-icon-precomposed" sizes="16x16" href="https://elastic.co/favicon_16x16.png"/>
-<link rel="icon" type="image/png" href="https://elastic.co/android-chrome-192x192.png" sizes="192x192"/>
-<link rel="icon" type="image/png" href="https://elastic.co/favicon-96x96.png" sizes="96x96"/>
-<link rel="icon" type="image/png" href="https://elastic.co/favicon-16x16.png" sizes="16x16"/>
-<link rel="icon" type="image/png" href="https://elastic.co/favicon-48x48.png" sizes="48x48"/>
+@* See https://github.com/elastic/elastic-marketing-website/blob/a8e4760249ddc8fe62bfa20efd28fdd85a0576f5/src/components/Seo.js#L200 *@
+<link rel="icon" href="/favicon.ico" sizes="32x32"/> @* for browsers that don't support svg favicon *@
+<link rel="icon" href="/favicon.svg" type="image/svg+xml"/>
+<link rel="apple-touch-icon" href="/apple-touch-icon.png" sizes="180x180"/>