[NO GBP]Fixes ethereal charging and recharge station charge speed. (#82483)

## About The Pull Request
Fixes many instances of things not charging ethereals properly. Scales
all things that are meant for charging/taking from the ethereal stomach
by STANDARD_CELL_CHARGE, so we never run into this issue again. Ethereal
stomachs now store a cell inside them, and uses that for the charge
instead of tracking a variable. Fixes recharging stations not being able
to charge ethereal stomachs. The ethereal signal proc attempted to feed
a callback datum to adjust_charge(), which caused a runtime. Changes
that by invoking the charge_cell callback instead.

Also fixes recharge station charging speed. They weren't converted
correctly. Also formats their charging speed in their description, and
displays power rather than referencing cycles.
## Why It's Good For The Game
So ethereals charge properly.

Closes #82470
## Changelog
🆑
fix: Fixes many instances of energy sources for ethereals supplying a
thousand times less energy than intended.
fix: Fixes recharging stations not being able to charge ethereals.
fix: Fixes recharge stations charging too fast.
qol: Recharge stations display their recharging speed in formatted
power, rather than unformatted energy per cycle.
/🆑

---------

Co-authored-by: san7890 <the@san7890.com>

code/modules/mod/mod_core.dm

@@ -262,7 +262,7 @@
 
 /obj/item/mod/core/ethereal/charge_amount()
 	var/obj/item/organ/internal/stomach/ethereal/charge_source = charge_source()
-	return charge_source?.crystal_charge || ETHEREAL_CHARGE_NONE
+	return charge_source?.cell.charge() || ETHEREAL_CHARGE_NONE
 
 /obj/item/mod/core/ethereal/max_charge_amount()
 	return ETHEREAL_CHARGE_FULL