Move documentation images up a level

Having this under doc rather than doc/source seems to make more
sense. In addition, I think this will prevent the documentation build
from looking in here for files to build (otherwise, I think I would need
to add this directory to the exclude list in conf.py).

Author: billsacks

.gitignore

@@ -5,7 +5,7 @@ manage_externals.log
 /tools/PTCLM/
 /cime/
 /components/
-/doc/source/images/
+/doc/images/
 
 # ignore svn directories
 **/.svn/**

Externals_CLM.cfg

@@ -13,7 +13,7 @@ tag = PTCLM2_20200121
 required = True
 
 [doc-images]
-local_path = doc/source/images
+local_path = doc/images
 protocol = git
 repo_url = https://github.com/ESCOMP/CTSM-doc-images.git
 hash = 0f039e7a043fabfce91ddf4f41186a3014603aac