Final MARBL modifications for CESM3

[mnlevy1981]

This PR will eventually address all issues in https://github.com/NCAR/MOM6/milestone/6 but for now it

1. Adds optional print_lev argument to print_marbl_log()

Fixes #432
Fixes #433

[klindsay28]

According to an answer on Stack Overflow, it is not okay to write to an internal file, i.e., a character string, and include that string on the right-hand of write statement.

[mnlevy1981]

According to an answer on Stack Overflow, it is not okay to write to an internal file, i.e., a character string, and include that string on the right-hand of write statement.

bummer! I guess the options are to either have very similar write() statements in both branches of the if statement, write the string without the level number to a temporary string and then either copy it or write it + level information, or to use the // concatenate operator (which might not format the integer level number as nicely as write)

[klindsay28]

In my sandbox, my adhoc implementation had very similar write() statements in both branches of an if statement, but I think this is an invitation to trouble down the road if the format gets edited in one branch and and not the other. How about something like the following untested pseudocode, which might be what you're suggesting as your option 2:

if (print_lev_loc) then
  write(message_suffix, "(A,I0)") ', Level: ', tmp%ElementInd
else
  message_suffix = ''
endif
write(message_location, "(A,F8.3,A,F7.3,A,I0,A,I0,A,I0,A)") &
  ...
  trim(message_suffix)

[mnlevy1981]

44a9940 fixes #433 (adding previously hard-coded variables to control structure and letting us modify them via MOM_input or MOM_interface changes)