some old log files are not pruned correctly

[mmguero]

clean-processed-folder.py in the filebeat container has the job of removing old Log files once they've been processed.

I discovered two problems:

1. Windows Event file archives (evtx) are not cleaned due to their MIME type being too generic (application/octet-stream)
2. Some Zeek logs can smell like HTML files (e.g., HTML document, ASCII text, with very long lines, text/html)

We need to handle these two cases.