Support model-to-measured DHW comparison

[chipbarnaby]

Description

Changes

1. Allow imports at subhourly interval. Formerly the shorted interval supported was hourly.
2. Add several inputs to allow providing inputs directly to portions of the DHW model for test purposes

• DHWSYS wstUseTest, wstInletTest, wsHwUseTest, wsTRLTest, wsVolRLTest
• DHWHEATER whTankTInit

3. Changed HPWH submodule to point to BigLadder fork of HPWHsim

Motivation: support model-to-measured comparisons using central heatpump water heater measured data.

Changes associated with subhour import are entirely internal.

Test inputs for DHWSYS and DHWHEATER are all defaulted to "do not use". Internal logic at the subhour and tick levels apply the test values to simulation working variables.

No results changes for pre-existing cases.

[nealkruis]

This is okay to merge once the conflicts have been addressed. Other branches should be updated ASAP to avoid confusion between remote HPWHsim repos.