[Bug] Radon Crashes When Krist is Down

[creeloper27]

I am now setting up a new Radon shop and I got the error /radon.lua:1390: /radon.lua:6467:

Apperantely this happens because Krist is currently Down, this situation should not crash Radon tho, a catch should be created for this scenario.

Also idealy it would be nice to display on the main screen that Kirst is Down and that the shop cannot accept puchases at the moment.

[migeyel]

TST payments also don't depend on Krist. The shop shouldn't refuse all payments just because one node happens to be down.