Initial rework of packet filter framework.

- Large rework on packet filter framework to make many things easier.
   - Removed the PacketFilter::all_packets variable because it was confusing.
   - New variable (PacketFilter::enable_auto_protocol_capture_filters) to re-enable the old filtering model of only sniffing ports for analyzed protocols.
   - In progress plugin model for adding filtering mechanisms.
   - New default single item for capture_filters = { ["default"] = PacketFilter::default_capture_filter };
   - Mechanism and helper functions to "shunt" traffic with filters.

- Created the Protocols framework to assist with reworking how base protocol scripts are registered with DPD and other things.
   - Protocols framework creates BPF filters for registered analyzers. (if using PacketFilter framework in that mode).

scripts/base/protocols/ssh/main.bro

@@ -6,6 +6,7 @@
 ##! is not attempted if the connection size analyzer isn't enabled.
 
 @load base/frameworks/notice
+@load base/frameworks/protocols
 @load base/utils/site
 @load base/utils/thresholds
 @load base/utils/conn-ids
@@ -73,11 +74,10 @@ export {
 	global log_ssh: event(rec: Info);
 }
 
-# Configure DPD and the packet filter
-redef capture_filters += { ["ssh"] = "tcp port 22" };
-redef dpd_config += { [ANALYZER_SSH] = [$ports = set(22/tcp)] };
-
-redef likely_server_ports += { 22/tcp };
+global analyzers = { ANALYZER_SSH };
+redef Protocols::analyzer_map["SSH"] = analyzers;
+global ports = { 22/tcp };
+redef Protocols::common_ports["SSH"] = ports;
 
 redef record connection += {
 	ssh: Info &optional;