Remove investing information

- Removed "Invest" from unauthenticated home page in Navbar
- Removed button/link from promo area of authenticated home page in
sidebar
- Updated Investors page to remove link leaving two beyind (reports)

app/views/about/investors.html.haml

@@ -5,8 +5,6 @@
   .box-widget
     .rich-formatting
       %h2 Investors
-      %p
-        = link_to 'Invest in Gab', 'https://invest.gab.com'
       %p
         = link_to '2018 Annual Report', 'https://www.sec.gov/Archives/edgar/data/1709244/000114420419021378/tv519744_annualreport.pdf'
       %p