Refactor convert_wildcard_to_*

[paalbra]

It probably makes sense to refactor convert_wildcard_to_filter and convert_wildcard_to_regex after #134 gets resolved.

convert_wildcard_to_filter isn't in use. Maybe just remove it?

convert_wildcard_to_regex might lead to this pattern:

params = {}
param, value = convert_wildcard_to_regex('name', args.name)
params[param] = value

Make input and output a dict probably makes more sense:

params  = convert_wildcard_to_regex({'name': args.name})