Feature: Add map view for visualizing connections

[elesiuta]

I've seen this requested a couple times in forums, so if someone wants to implement it, it could probably be done with https://plotly.com/python/bubble-maps/ in a new tab with https://dash.plotly.com/dash-core-components/tabs

All the code for the dash is under the function ui_dash and the connection data is queried from the sqlite db. The location is looked up with get_geoip for each IP and not stored in the sqlite db.

To help with debugging, you can test it with DASH_DEBUG=True python3 picosnitch.py start-dash