Stochastic physics changes

[MingjingTong-NOAA]

Description
This is part of the changes to update the use of stochastic physics from a new and updated repo

How Has This Been Tested?
A forecast test was run to compare with the main branch and the results are bit-wise identical.

Checklist:

• [x ] My code follows the style guidelines of this project
• I have performed a self-review of my own code
• [x ] I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• [x ] My changes generate no new warnings
• [x ] Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included

[laurenchilutti]

Is this still a draft or ready for a review?

[MingjingTong-NOAA]

Sorry, I change it to be ready to review. Thanks.

[JosephMouallem]

Is there a specific reason for this name change? I would prefer keeping the current name to avoid having to update all of our runscripts.

[MingjingTong-NOAA]

I change the name, because I introduced another 'first_time_step' variable in physics here

./GFS_layer/GFS_typedefs.F90: logical :: first_time_step !< flag signaling first time step for time integration routine

This variable is used in the atmos_model.F90

./atmos_model.F90: IPD_control%first_time_step = .false.
./atmos_model.F90: IPD_control%first_time_step = .true.

Also, I think write_first_time_step better indicates the meaning of this variables.