Highlights:
- Reduced all DHCP events into a single dhcp_message event. (removed legacy events since they weren't widely used anyway)
- Support many more DHCP options.
- DHCP log is completely reworked and now represents DHCP sessions
based on the transaction ID (and works on clusters).
- Removed the known-devices-and-hostnames script since it's generally
less relevant now with the updated log.
Old event prototypes have changed and the events are broken right
now and may be removed in favor of the new generic "dhcp_message"
event.
DHCP option parsing is abstracted from the main code base of the
protocol parser and are all now located in their own file.
Documentation, tests, and final code cleanup are still pending.
