Add outputs for mixed hot water usage along with hot water usage

[jmaguire1]

Right now we default the hot water usage for all end uses (fixtures, associated waste, clothes washers, and dishwashers). For mixed end uses (fixtures and associated waste), it'd be nice to have the hot and total (cold + hot) usage, since the inputs are generally the total and then Fmix gets calculated based on the mains water temperature to determine what fraction of the total is hot.

I think this is relatively straightforward to just default to including "Total Water Volume" outputs as well as "Hot Water Volume" Outputs. We could alternately include "Cold Water Volume", but total is generally what we want to look at. Total volume and hot volume will be the same for CW and DW, so we probably only need this for fixtures and waste.

For reference these are the available outputs in E+ form the .rdd:

Output:Variable,*,Water Use Equipment Hot Water Volume,hourly; !- HVAC Sum [m3]
Output:Variable,*,Water Use Equipment Cold Water Volume,hourly; !- HVAC Sum [m3]
Output:Variable,*,Water Use Equipment Total Volume,hourly; !- HVAC Sum [m3]