Report sockets opened by debugpy

[paulacamargo25]

In order to implement the Port Attributes API. We need to know the port info that debugpy generates for the debugging process. You can send this as a log message that we can track and then disable port forwarding on those ports.

[int19h]

@paulacamargo25
The protocol is as follows: when client connects to the adapter, unless it is a secondary session (i.e. subprocess attach), it receives a debugpySockets event looking something like this:

        {
              "seq": 6,
              "type": "event",
              "event": "debugpySockets",
              "body": {
                  "sockets": [
                      {
                          "host": "127.0.0.1",
                          "port": 63435,
                          "internal": false
                      },
                      {
                          "host": "127.0.0.1",
                          "port": 63437,
                          "internal": true
                      },
                      {
                          "host": "127.0.0.1",
                          "port": 63436,
                          "internal": true
                      }
                  ]
              }
          }

Thereafter, such events are sent whenever the adapter opens or closes a port, with the content of "sockets" updated accordingly. At any given moment, the only ports that should be forwarded are those that were present in the most recent such event with ["internal"] === false.

See #1404 for implementation.