Move FileIOSharedMod, NCIOMod, MAPL_LocStreamMod to base3g/; re-export through MAPL umbrella (#4882)

* Extend mapl3g_FileIO WRITE_PARALLEL with scalar/1d integer and real overloads (refs #4879)

* Move FileIOSharedMod and NCIOMod to base3g/, re-export through MAPL umbrella (refs #4874, #4879)

- Move FileIOShared.F90 and NCIO.F90 from base/ to base3g/ with
  temporary internal module names (mapl_FileIOShared, mapl_NCIO)
- Leave thin compatibility wrappers in base/ under original module
  names (FileIOSharedMod, NCIOMod) so existing callers are unaffected
- Copy write_parallel.H and read_parallel.H to base3g/include/
- Update base3g/CMakeLists.txt with new sources and dependencies
- Re-export ArrDescr, ArrDescrInit, ArrDescrSet, MAPL_VarRead,
  MAPL_VarWrite, MAPL_NCIOGetFileType, MAPL_IOGetNonDimVars,
  MAPL_IOCountNonDimVars, MAPL_IOChangeRes, MAPL_IOCountLevels
  through mapl_base3g so they are available via 'use MAPL'

* Move MAPL_LocStreamMod to base3g/ (module mapl_LocStreamMod_impl); leave thin wrapper in base/ (refs #4874)

Author: tclune

base/CMakeLists.txt

@@ -27,8 +27,7 @@ esma_add_library(
 # We don't want to disable good NAG debugging flags everywhere, but we still need to do it for
 # interfaces (e.g. MPI) that allow multiple types for the same argument (eg buffer).
 if (DUSTY)
-  set_property( SOURCE FileIOShared.F90 NCIO.F90
-                PROPERTY COMPILE_FLAGS ${DUSTY})
+  # FileIOShared.F90 and NCIO.F90 are now thin wrappers; no DUSTY flags needed
 endif ()
 
 target_link_libraries(${this} PRIVATE OpenMP::OpenMP_Fortran)