Implement a pass-through configuration

[glaslos]

Using TCP and UDP proxy or exclusion in the iptables rule spec (like port 22 for ssh).
We used the iptables rule exception for SSH to allow connectivity even if Glutton failed or crashed without flushing the rules.
There is a benefit in using a proxy in Glutton for pass-through for non-critical ports as we maintain visibility. Being able to collect at least metadata allows us to maintain a full picture directly from Glutton.

Sample rule for pass-through:

rules:
  - match: tcp dst port 1234
    type: passthrough

[jerryyummy]

i would like to solve it. so there are something to do:

1. Proxy all TCP/UDP traffic
2. Support multiple excluded ports
3. Ensure Glutton can still capture malicious traffic
   is it right?

[jerryyummy]

@glaslos hi, i already run the porject but found that although some ports have been configured in the yaml file, but i can not use curl to access these ports, i can only access the 5000 port. so may i ask how to reproduce the situation that glutton can handle other ports(like 8080) , so i can try to implement passthrough

[jerryyummy]

pls have a check , #172