Documentation issues related to case creation scripts

[jjokella]

Some small issues that popped up when guest scienties Mehdi Khaki went through it.

1. the file mkscripgrid.py cannot be found in the static file generator repo:

eCLM/docs/users_guide/case_creation/1_create_grid_file.md

Lines 14 to 26 in c9f3348

	## 1. Create SCRIP grid file with `mkscripgrid.py`
	To use `mkscripgrid.py`, first open the script (for example using vim text editor) and adapt the variables that describe your grid. These include your grid name, the four corner points of your model domain as well as the resolution (lines 42-50 of the script). Then you can execute the script:
	```sh
	python mkscripgrid.py
	```
	```{attention}
	The `mkscripgrid.py` script requires numpy and netCDF4 python libraries to be installed (use pip install to do that if not already installed).
	```
	The output will be a SCRIP grid netCDF file containing the grid dimension and the center and corners for each grid point. It will have the format `SCRIPgrid_"Your grid name"_nomask_c"yymmdd".nc`

2. surfdata should be added to the path here:

eCLM/docs/users_guide/case_creation/4_create_surface_file.md

Line 18 in c9f3348

export CSMDATA="/p/scratch/cslts/shared_data/rlmod_eCLM/inputdata/" # this works for JSC users only, for non JSC users see below

[kvrigor]

There's a plan to replace the eCLM case creation guide with the more recent guides in eCLM_static-file-generator. Ongoing discussion here: HPSCTerrSys/eCLM_static-file-generator#2