Bundled Themes: Twenty Seventeen add Telegram and Whatsapp support to Social Media Menu.

Adds Telegram and Whatsapp support and SVG's to Social Media Menu.

Props cpasqualini, audrasjb, laurelfulford, karmatosed, ibdz.
Fixes #43999.
Built from https://develop.svn.wordpress.org/trunk@48027


git-svn-id: https://core.svn.wordpress.org/trunk@47795 1a063a9b-81f0-0310-95a4-ce76da25c4cd