vmonkey, read_ole_fields: use zipfile with in-memory buffer instead of temp file

[decalage2]

In several places a temporary file on disk is used to parse a zip file and extract files. It should all be done in memory to avoid issues with temp files.
(search for "unzip", "/tmp", "tempfile", ...)

Issues due to temp files on disk:

• exceptions on Windows when trying to delete temp file without closing the zipfile first
• if there is an antivirus running, it can detect and delete temp files before we process them

[decalage2]

done for vmonkey/pull_embedded_pe_files in commit b0fb1b2