Add CFP buttons to every social media

[ai]

• Add We are looking for speakers: [link] to Twitter account
• Post a tweet about speakers support (how exactly we will help) and steps to send talk. Then pin it to make it always in the top in Twitter account.
• Add Send talk (Maybe with better wording) to barcelonajs.com near the Follow Us! button
• Change BarcelonaJS/events to Submit your talk here