ZM cleanup - create zm_transport module

[whannah1]

Create a new module to contain methods for the ZM tracer and momentum transport methods.

[BFB]

[whannah1]

The following tests pass on Chrysalis:

  e3sm_atm_developer_intel
  e3sm_atm_developer_gnu
  SMS_Ld32.ne30pg2_r05_oECv3.F2010.chrysalis_intel
  SMS_Ld32.ne30pg2_r05_oECv3.F2010.chrysalis_gnu
  SMS_Ld32.ne4pg2_oQU480.F2010.chrysalis_intel
  SMS_Ld32.ne4pg2_oQU480.F2010.chrysalis_gnu

The performance of the SMS_Ld32 tests are very close, so there's no notable performance impact

SMS_Ld32.ne30pg2_r05_oECv3.F2010.chrysalis_intel:
    base: ATM Run Time:    3722.581 seconds      116.331 seconds/mday         2.03 myears/wday
    test: ATM Run Time:    3741.495 seconds      116.922 seconds/mday         2.02 myears/wday

          name              on  processes  threads        count      walltotal   wallmax (proc   thrd  )   wallmin (proc   thrd  )
    base: "a:zm_conv_tend"   -        128      256 2.360832e+06   1.560145e+04    69.644 (     6      0)    49.213 (    27      0)
    test: "a:zm_conv_tend"   -        128      256 2.360832e+06   1.593433e+04    70.822 (     6      1)    53.104 (    54      0)

[AaronDonahue]

Looks good to me. Just had one question about a possibly unused variable

[AaronDonahue]

Do any of these routines use lchnk? I did a quick search and couldn't find any reference to it other than having it be declared.

[whannah1]

Good catch! I think this and some other variables were just added to all ZM subroutines by default in case they were needed, but I can't think of a good justification for leaving this in, so I'll remove it from the interface.

[whannah1]

fixed.