Use chrome.socket.secure for SSL connections

[beaufortfrancois]

Since https://codereview.chromium.org/76403004, we can now use chrome.socket.secure to start a TLS client connection over a connected TCP client socket.

This way, you could remove https://github.com/flackr/circ/commit/36f0ef843207d8b34bda366ef65c04f0122efd98

[flackr]

FYI I did try using chrome.socket.secure but it seems to require additional authentication that most SSL IRC servers don't provide, e.g.

/server chat.freenode.net +6697
Socket Error: failed to secure socket: net::ERR_SSL_CLIENT_AUTH_CERT_NEEDED (error 110)