refactor(favicon); change favicon related setup

exampleSite/config/_default/params.toml

@@ -9,9 +9,9 @@ bundled = true
 # generate these with https://realfavicongenerator.net
 favicon = true
 # modern SVG favicon to use in place of older style .png and .ico files
-svgFavicon = ""
-# Safari mask icon color
-iconColor = "#000000"
+svgFavicon = "/dot.svg"
+# fallback png favicon for unsupported browsers
+svgFaviconFallback = "/dot.png"
 
 # page config
 [page]