ocrd workspace remove: recursive is not passed
When running

    ocrd workspace -d bucher1806_florae remove-group -fr GT

I get
```
Exception: fileGrp GT is not empty and recursive wasn't set
```

The culprit is here:
https://github.com/OCR-D/core/blob/f9c2b6c825186d6021d28b2deb9616f645ccfb68/ocrd/ocrd/workspace.py#L248


diff --git a/ocrd/ocrd/workspace.py b/ocrd/ocrd/workspace.py
index f6f82aae..3a578323 100644
--- a/ocrd/ocrd/workspace.py
+++ b/ocrd/ocrd/workspace.py
@@ -245,7 +245,7 @@ class Workspace():
                     if f_dir:
                         file_dirs.append(f_dir)
 
-        self.mets.remove_file_group(USE, force=force)
+        self.mets.remove_file_group(USE, force=force, recursive=recursive)
 
         # PLEASE NOTE: this only removes directories in the workspace if they are empty
         # and named after the fileGrp which is a convention in OCR-D.
['ocrd/ocrd/workspace.py']