New tls module

[tehmoon]

This module will be used to perform some TLS inspection. The goal is to grab the client hello and dial the requested server on the same listening port. Once it's dial, there are two options:

• either pass the clienthello to the server and patch the two connections
• generate a new clienthello, grab the serverhello, generate certificates on the fly by copying the

features:

• inspect mode: double handshake generating a new certificate on the fly
• bypass mode: forwarding handshake depending on SNI
• connect-to: use address instead of SNI for the remote address
• endpoint: don't re-encrypt the traffic
• generate own CA
• output CA certificate
• set server certificate/key

I tried to do a PoC but it's really hard:

 - start a tcp server
 - wait for a tcp connection
 - duplicate a reader from the tcp connection to a buffer
 - wrap tcp connection into a tls connection
 - register callback for client hello
 - start handshake
 - when callback triggers
   - send servername from clienthello to dedicated buffer goroutine
   - read the entire buffer from the goroutine
   - dial tcp connection from servername
   - send the buffered first bytes which should be the client hello to the new tcp socket
   - pipe the conn (not the tls conn) to the new tcp socket read/write

Edit:

Merge the new module with tcp-server since the module currently just sends the bytes through the channel.

[tehmoon]

80 Got merged! I did not merge it with tcp-server because I don't see the need right now.