dtend: add missing tendencies and fix bugs in convection tendencies (N…

…CAR#82)

* Fix incorrect units in dtend metadata

* Point to Sam's FV3 for testing purposes

* Bug fixes to dtend support:

1. Store rtg (AKA clw AKA qtr) instead of gq0 in DCNV and SCNV
pre/post for schemes that use convective transport. Tracers handled
solely by convective transport (ones not in rtg) are reported as
convective transport tendencies. Tendencies for variables in rtg are
reported as dcnv and scnv tendencies.

2. Report TKE tendencies from gfs v16 PBL.

3. Add diagnostic tendencies to drag_suite

4. Only report rayleigh damping tendencies if rayleigh damping is enabled

5. List all possible diagnostic tendencies, even if they are not
enabled. In the output, label them "selected" or "disabled."

6. Add phys_tend to the fv3_rap suite.

* Merge gsl/develop into FV3 and FV3/ccpp/physics

* Add phys_tend to suite_FV3_GSD_SAR and remove some debug prints

* Remove some debug prints and commented-out code.

* Correct error in dtend variable availability list print.

* Enable convtrans diagnostic tendencies for number concentrations and qrimef.

* Disable cnvtrans diagnostic tendencies for schemes that do their own diagnostic tendency reporting.

* Point to gsl repositories