v15: Convert patterns to JSON input files.

Tallow will now read JSON files from /usr/share/tallow/ and /etc/tallow
and parse them to retrieve filters and patterns. The sshd patterns
are converted to JSON and used to test this change.

If a file exists in /etc/tallow with the same name as a file in
/usr/share/tallow, only the file in /etc/tallow will be parsed.

This change allows much more dynamic insertion of rules and people
to create custom patterns and filters and monitor the logs of other
daemons besides sshd that may be subject to brutefoce login attempts.

Potential use cases:
- IMAP/POP services
- SMTP
- HTTP services permitted they log to syslog
- DNS servers logging malformed requests
- etc.