Implement thermo_water_update scheme (non-portable wrapper to cam_thermo_water_update)

[jimmielin]

Originator(s): @jimmielin

Summary (include the keyword ['closes', 'fixes', 'resolves'] and issue number):

Closes #177, implementing thermo_water_update scheme to call cam_thermo_water_update.

Describe any changes made to the namelist: N/A

List all files eliminated and why: N/A

List all files added and what they do:

Implement thermo_water_update scheme
A schemes/thermo_water_update/thermo_water_update.F90
A schemes/thermo_water_update/thermo_water_update.meta

List all existing files that have been modified, and describe the changes:
(Helpful git command: git diff --name-status development...<your_branch_name>)

Include thermo_water_update scheme in CAM7 suite
M suites/suite_cam7.xml

List any test failures:

Is this a science-changing update? New physics package, algorithm change, tuning changes, etc? Yes

[jimmielin]

Marking as draft until ESCOMP/CAM-SIMA#316 is merged and CAM7 test failure is resolved (ESCOMP/CAM-SIMA#335) so this "scheme" can be fully tested.