Update opf parser to support refines meta elements

[advplyr]

Brief summary

Parse OPF v3
See #4109

Which issue is fixed?

None

In-depth Description

In OPF v3 meta elements can have a refines attribute that is an ID of another element it is describing.

In this example the role of the dc:creator element is in the refines meta element.

<package version="3.0" unique-identifier="uuid_id" prefix="rendition: http://www.idpf.org/vocab/rendition/#" xmlns="http://www.idpf.org/2007/opf">
  <metadata>
    <dc:creator id="create1">Nevil Shute</dc:creator>
    <meta refines="#create1" property="role" scheme="marc:relators">aut</meta>
    <meta refines="#create1" property="file-as">Shute, Nevil</meta>
  </metadata>
</package>

How have you tested this?

Added test case