This commit changes the logic that is used to tracks connection
establishment - and moves it from scriptland into the core.
TLS 1.3 connection establishment is much more finnicky for us than the
establishment of earlier versions - since we cannot rely on the CCS
message anymore (which is meaningless and not sent in a lot of cases).
With this commit, the ssl_encrypted_data message gets raised for
encrypted TLS 1.3 handshake messages - which is much more correct than
the behavior before that just interpreted them as plaintext messages.
I will refine this a bit more - at the moment the connection established
event happens a bit too early - earlier than TLS 1.3 connections
actually can be estasblished.
Part of GH-1323