Renames delta time to be a more obvious name (#74654)

This tracks the seconds per tick of a subsystem, however note that it is
not completely accurate, as subsystems can be delayed, however it's
useful to have this number as a multiplier or ratio, so that if in
future someone changes the subsystem wait time code correctly adjusts
how fast it applies effects

regexes used

git grep --files-with-matches --name-only 'DT_PROB' | xargs -l sed -i
's/DT_PROB/SPT_PROB/g'
git grep --files-with-matches --name-only 'delta_time' | xargs -l sed -i
's/delta_time/seconds_per_tick/g'

code/modules/wiremod/shell/brain_computer_interface.dm

@@ -274,7 +274,7 @@
 		to_chat(owner, span_info("[circuit_component.parent]'s [cell.name] has <b>[cell.percent()]%</b> charge left."))
 		to_chat(owner, span_info("You can recharge it by using a cyborg recharging station."))
 
-/datum/action/innate/bci_charge_action/process(delta_time)
+/datum/action/innate/bci_charge_action/process(seconds_per_tick)
 	build_all_button_icons(UPDATE_BUTTON_STATUS)
 
 /datum/action/innate/bci_charge_action/update_button_status(atom/movable/screen/movable/action_button/button, force = FALSE)