Clicking on the "home"/Keybase logo icon when logged in takes you to the public homepage instead of the dashboard

## Background

When you're not logged in, visiting keybase.io shows you a public homepage describing what Keybase is and how to use it.

## Issue

When you're signed in, clicking on the logo (which some assume is the "home" action) shows them this public page. I think this isn't good UX.
## Suggested Solution

Instead, clicking on the logo/home should show them a "dashboard" page, which can be pretty similar to the current profile page (/username) with more info, such as incoming messages or updates.

## Affected Resources
- Keybase website (http://keybase.io)
## Priority

Low

Start at the Keybase website's logo/home navigation for signed-in users and compare its destination with the public keybase.io homepage. Review the existing /username profile page as the suggested dashboard reference. Done means the signed-in logo/home action opens a dashboard rather than the public homepage, with the dashboard scope agreed.

Written by the indexing model from the issue text.