Add vegetation temperature outputs for crop stress work

[ShannonRoos]

Description of changes

added option of outputting TVMAX and TVMIN (similar to existing TV output, but max and min instead of average), daytime vegetation temperature (TVDAY), and night-time vegetation temperature (TVNIGHT).

Specific notes

Contributors other than yourself, if any: @samsrabin

CTSM Issues Fixed (include github issue #): None

Are answers expected to change (and if so in what way)?
no, I only ouput exisiting variables (and are inactive by default).

Any User Interface Changes (namelist or namelist defaults changes)? Adds optional history variables:

• TVMAX
• TVMIN
• TVDAY
• TVNIGHT

Does this create a need to change or add documentation? Did you do so?
Variable list page should be updated, but this PR doesn't do that (yet?).

Testing performed, if any:

• Tested suite clm_short; no diffs.
• Variables show up if requested.