veraPDF-validatio: Use of Default `DocumentBuilderFactory` leads to XXE When Processing Untrusted PDFs

Summary veraPDF-validation has an XML External Entity XXE vulnerability in two PDF parsing paths validate and GFPDAcroForm.getdynamicRender. A malicious/crafted PDF supplied to a veraPDF consumer can lead to the expansion of external entities while parsing rich-text annotation/form-field values o...