Json output olemeta

[remotephone]

Update olemeta to provide json output with -o flag and to be run imported into other tools.

The olemeta tool works great to provide a table format for interactive use of the tool. I want to be able to import the tool into other scripts to automate some triage of malicious documents. This change would allow the user to provide a -o flag at runtime to generate output in json. Normal use of the tool would not change, but it could now be imported into other tools with something like:

from oletools import olemeta
import olefile

with open('file.doc', 'rb') as file:
    output = 'json'
    ole = olefile.OleFileIO(file)
    meta = olemeta.process_ole(ole)
    json_metadata = olemeta.process_output(meta, output)
    print(json_metadata)