Resolve units discrepancy in `water_use.py`

[timothy-nunn]

When the various water use variables are output they are described being m^3/day:

PROCESS/process/models/water_use.py

Lines 116 to 123 in bd4752b

	if output:
	po.ovarre(
	self.outfile,
	"Volume used in cooling tower (m3/day)",
	"(waterusetower)",
	self.data.water_use.waterusetower,
	"OP ",
	)

However in the data structure the units are listed as m3:

PROCESS/process/data_structure/water_usage_variables.py

Lines 44 to 45 in bd4752b

	waterusetower: float = 0.0
	"""total volume of water used in cooling tower (m3)"""

The correct units need to be established and the units need to be corrected so they are consistent.