pico w: implement sslsocket bind, listen, accept

[jepler]

This works! Before it was broken with high probability due to adafruit/Adafruit_CircuitPython_HTTPServer#19 -- make sure you have that fix when testing.

https-server-example.zip includes a self-signed certificate for example.com from https://regery.com/en/security/ssl-tools/self-signed-certificate-generator. In my setup I could use a properly trusted certificate, but it would not be OK or useful to attach that certificate and private key to this PR.

Note that it takes quite some time for the picow to do all the things -- about 7.5s to curl the tiny index file. it's not practical. but it does work.

With the self-signed certificate you can test with curl --insecure. Note that curl -insecure (one dash) is accepted but doesn't work!

In Firefox browser with proper certificate:

In Firefox browser with self-signed certificate, after clicking through security dialogs:

[dhalbert]

People have reported using this, so I'll merge. Thanks!