Allow medicade stations to be recharged

Sometimes you miss the station without a power cell and it goes on a bit of an adventure with your team until you find a station that already has a cell, sometimes that cell only has 1-2 charges but you’ve got a spare cell in hand.

Let players switch out the cells if they had a spare anyway.

_

I once stubbornly carried a power cell all the way to the evac point after someone asked why I was carrying it, the group found it hilarious.
At first I didn’t realise that someone else in the group had intentionally thrown it over the no-return ledge at the time as no one needed healing, so I just thought I’d found one and was taking it to the station.
I can only assume Hadron was pleased with the offering.