add a script for rewinding an existing ldas run

[saraqzhang]

a standalone script that rewinds ldas run when in need of re-sync restart date/time in ldas and adas

[github-actions]

Label error. Requires at least 1 of: 0 diff, 0 diff trivial, Non 0-diff, 0 diff structural, 0-diff trivial, Not 0-diff, 0-diff, automatic, 0-diff uncoupled. Found:

[saraqzhang]

@gmao-rreichle
the script is put in src/Applications/LDAS_App/util/shared/.

[gmao-rreichle]

@saraqzhang, many thanks for adding the script! I made a few edits to clean it up a bit and also moved it to ./config, for lack of a better idea. In the broader sense, the script deals with setting up (configuring) an experiment, so it's probably ok there.
Please double-check my changes. Here's my commit with the edits (before the file was moved and renamed):
646f32a?w=1
Note that this link suppresses white-space changes.
Here's the same again with the white-space changes, which could be important for a csh script.
646f32a
I hope I didn't mess it up.

[saraqzhang]

@gmao-rreichle the edited version is cleaner and all correct. config/ is a more suitable dir to be .

[tclune]

cmake changes ok

[gmao-rreichle]

@weiyuan-jiang, @GEOS-ESM/cmake-team, please take a quick look at this small PR and, if ok, approve the CMake changes. Thanks!