Remove goto statements from source code

[SnowHydrology]

Work on the current NWM identified Fortran goto statements as a potential issue. Modern Fortran has moved away from goto statements for myriad reasons, some of which are discussed here.

There are two modules from which the gotos should be removed (https://github.com/NOAA-OWP/sac-sma/search?q=goto):

• sac/duamel.f
• sac/#duamel.f#

Alternative solutions include do loops, if statements, cycle, exit, and case.

This issue also needs fixing in Noah-OWP-Modular and Snow-17.

[andywood]

These are original codes from NWS OHD and to preserve continuity they are retained in original form, as long as the fortran compilers still allow it. i.e., not pretty but it works. The backup version #duamel.f# has been removed from the repo. This is true of Snow-17 and Noah-OWP-Modular as well, although some statement functions on the latter were compiler-obsolete and had to be removed.