Move Communities to own page

[nabramow]

Right now you can only find communities by browsing via the dashboard. This makes it hard to find or notice. Let's move the same functionality into its own page (for v1). There's lots more to improve but we'll start here.

Acceptance Criteria

• Create a communities page and add it to the Navbar after "Events"
• Change the link on the Dashboard page "Browse communities" to link to this page instead
• Also on the Dashboard under "Your communities", change the "browse communities" link to this new page
• Take the same functionality from this pop up and put it in this new page instead (I think you can just plop CommunityBrowser component in the page.
• Add "Don't see your community? Get it started!" at the bottom of this page (same as Dashboard has).
• Write some tests to check the routing works
• Once everything works, remove the old popup components