Make pattern property field name not assigned an index value defaults to 0

[mbkranz]

For inputted csv vlmd template files that have a regex in a json path header name (e.g., standardsMappings[\d+].url rather than an actual index (e.g., standardsMappings[0].url), assume \d+ = 0 for the csv data dictionary convert/exract function

[mbkranz]

Should be implemented/called somewhere around here

but probably good to create a function in utils.py that (1) checks for existence of digit regex and (2) replaces with 0?