Makes Exosuit Charging station fully buildable.

Adds the Power port design and circuit.
Changes recharge_station from a turf to a machine with 0 density and Crossed procs. This is also now buildable with a circuit and a design.
Fixes some relative pathing.
Would be good to make the code create this description from the part list in the future:
```dm
frame_desc = "Requires:<br>"
for(var/part in req_components)
    frame_desc += "    <em>[req_components[part]]</em>"
    part = text2path(part)
    frame_desc += "[initial(part.name)]<br>"
```