Path traversal in HtmlExporter.java and FileXmlExporter.java

Both HtmlExporter.java and FileXmlExporter.java use the prepareExportFileName method inherited from AbstractExporterImpl.java in forming a path to use for the zip file location (archivePath & zipFileName, respectively) which uses the user controlled space key[0] in the returned path and are thus vulnerable to path traversal.

[0] personal space keys are allowed to contain "." and "/" characters.