json2pcap: Added pcap masking and anonymization support

The script includes the following changes:
- Added pcap masking and anonymization support
- Support to mask/anonymize only portion of field
- Added reading from stdin
- Changed json to ijson library to support large files
- Migrated from text2pcap to scapy for pcap generation
- Added version to script

The development repo is located here
https://github.com/H21lab/json2pcap

Change-Id: I8fc5e282caa604e188f05818f7a2f8875afb8b73
Reviewed-on: https://code.wireshark.org/review/37371
Reviewed-by: Dario Lombardo <[email protected]>