Add more RH outputs

**Sam Rabin: Note that the thinking on this issue evolved from this first post; see discussion further in thread.**

RH_LEAF is identified as 'fractional humidity at leaf surface'
https://github.com/ESCOMP/CTSM/blob/6fad071dce82ab4cbf42f6cd47399bd463bd126a/src/biogeophys/PhotosynthesisMod.F90#L377

But in the SMS (use_hydrstress=.false.) Ball-Berry code, it looks like RH_LEAF is first set as the sunlit rh_leaf, but then will be rewritten by shaded rh_leaf if there is a shaded leaf phase of the canopy. This seems like a bug.
RH_LEAF is not populated with SMS-Medlyn or PHS.

I would suggest addressing this issue when unifying the PHS and SMS code and checking for any other leaf-level variables that may be inconsistently populated.

In the mean time, I wanted to document the issue for users who may be looking at RH_LEAF.