✨ Use MAX file group name instead of BEST

We were using the file group name BEST for what Kitodo seems to call
MAX by convention. So we use MAX now.

Currently, we work under the assumption that, if MAX exists in the METS
retrieved by OAI-PMH, it's not what we want and we replace it with our
own IIIF URLS with full size.

Fixes GH-43.

ppn2ocr

@@ -91,15 +91,20 @@ def make_workspace(ppn, workspace):
     remove_file_grp(mets, 'PRESENTATION')
     remove_file_grp(mets, 'LOCAL')
 
-    # Duplicate DEFAULT file group into a new file group BEST
+
+    # Delete MAX file group - we assume that, if it exists, it is not as
+    # we expect it, e.g. IIIF full URLs
+    remove_file_grp(mets, 'MAX')
+
+    # Duplicate DEFAULT file group into a new file group MAX
     format_ = 'tif'
     file_grp_default = mets.find('//mets:fileGrp[@USE="DEFAULT"]', namespaces=XMLNS)
     file_grp_best = deepcopy(file_grp_default)
 
-    file_grp_best.attrib['USE'] = 'BEST'
+    file_grp_best.attrib['USE'] = 'MAX'
     for f in file_grp_best.findall('./mets:file', namespaces=XMLNS):
         old_id = f.attrib['ID']
-        new_id = re.sub('DEFAULT', 'BEST', old_id)
+        new_id = re.sub('DEFAULT', 'MAX', old_id)
         f.attrib['ID'] = new_id
         f.attrib['MIMETYPE'] = mime_type_for_format(format_)
 
@@ -157,7 +162,7 @@ def ppn2ocr(ppn):
     # XXX
     #  subprocess.run([
     #     os.path.join(self_dir, 'run-docker-hub'),
-    #     '-I', 'BEST',
+    #     '-I', 'MAX',
     #     '--skip-validation'
     #  ])