replace mkdtemp() as default workdir with "work"

was causing a number of issues because it was using /tmp and also a new
folder for each run..
This makes it a subfolder of the output folder like it used to be,
though we don't archive it up by default..

hippunfold/config/snakebids.yml

@@ -291,10 +291,10 @@ parse_args:
 
   --workdir:
     help: |
-      Folder for storing working files. If not specified, a temporary folder
-      will be made in your system's temp directory (e.g. /tmp). You can also
-      use environment variables when setting the workdir, e.g. --workdir '$SLURM_TMPDIR'.
-    default: null
+      Folder for storing working files. If not specified, will be in "work/" subfolder 
+      in the output folder. You can also use environment variables when setting the 
+      workdir, e.g. --workdir '$SLURM_TMPDIR'.
+    default: work
     type: str
 
 

hippunfold/workflow/Snakefile

@@ -95,8 +95,6 @@ wildcard_constraints:
     template="[a-zA-Z0-9]+",
 
 
-if config["workdir"] == None:
-    config["workdir"] = mkdtemp()
 work = os.path.expandvars(config["workdir"])
 root = os.path.expandvars(config["root"])