When write_hist_at_0h_rst=.true., will now apply to user-def streams

[jhruppert]

The first line should be a single-line "purpose" for this change

TYPE: bug fix/enhancement

KEYWORDS: wrf, wrfv4, restart, output streams

SOURCE: James Ruppert (University of Oklahoma)

DESCRIPTION OF CHANGES:
Problem:
When running WRF from as a restart, the option write_hist_at_0h_rst would only apply to the default history stream. Now, when this option is set to true, it will also apply to special user-defined streams. This is required to maintain a consistent number of output time steps per file with multiple time steps writing to a single file, which is often preferred for multiple-day runs.

Solution:
Added an additional loop over history streams with CALL med_hist_out when the following condition is met:
IF ( (config_flags%restart) .AND. ( currTime .EQ. startTime ) .AND. ( config_flags%write_hist_at_0h_rst ))

ISSUE: For use when this PR closes an issue.
While it's apparently not a very common need, it is something we are now using across multiple projects (and likely more in the future) so it would help to have it included moving forward. There is a thread on the wrf forum at https://forum.mmm.ucar.edu/threads/to-the-wrf-developers-write_hist_at_0h_rst-for-user-defined-output-streams.16824/

LIST OF MODIFIED FILES:
share/mediation_integrate.F

TESTS CONDUCTED:

1. Verified that this change works: when option is set to true, history write-out at first time step of a restart now applies to both the default history stream and a user-defined stream (tested with stream 7).
2. None of the Jenkins tests appear to fail.

RELEASE NOTE:
When the namelist option write_hist_at_0h_rst is set to .true. under &time_control, history write-out will now be conducted for the first time step for both the 0th stream (wrfout* files) and any special user-defined streams being implemented.

[weiwangncar]

The regression test results:

Test Type              | Expected  | Received |  Failed
= = = = = = = = = = = = = = = = = = = = = = = =  = = = =
Number of Tests        : 23           24
Number of Builds       : 60           57
Number of Simulations  : 158           150        0
Number of Comparisons  : 95           86        0

Failed Simulations are: 
None
Which comparisons are not bit-for-bit: 
None