[atlas] New measurement UI

Hello,

I'd like to give a bit of early feedback to the new atlas UI. All in all
it's nice, but I have trouble with the measurement creation in two points:

Selection of probes: I like the selecting via map, but usually something
like "50 out of central europe" is good enough. If that is possible, how
would you do that?

A bug about credit evaluation: trying to create a measurement with DNS6
queries for hostname.bind CH TXT with more than a handful of probes
(roughly 50-70 probes I guess) fails as the interfaces believes this to
require over 1000000 credits.

As for map representation (which I use quite often), I think I prefer
the old map without aggregation. But that's quite personal. BTW, the new
one seems to fail on response diversity for DNS.

best,
Gilles