Feature/#30 allow only logged in users to read user data

[reinierl]

This should fix #30 by setting the appropriate security rules, and hiding functionality that uses other people's data from non logged in people.

[bidsinga]

Guess if we only allow logged in users to enter the map, we should also change this is layouts/Footer.vue. Wouldn't it be better to allow logged out users to at least access the POI's and country pages, and to hide the user markers in the map?

[reinierl]

Logged out users can still go to the map if they really really want to and type the URL directly at this point. I just removed the navigation so they don't go there only to be disappointed by the things that don't work.

What would you say if I created a follow-up issue for reinstating the map for logged out users? And then we should also make sure that we take care to give them a decent experience.

[reinierl]

@bidsinga I've created the follow-up issue: #107.