fix: Add SNI for TLS connections if one is not set

Signed-off-by: amir-khassaia <amir.khassaia@gmail.com>

Signed-off-by: amir-khassaia <amir.khassaia@gmail.com>

…e app to keep the library simple

refactor: revert SNI handling and add a pre connect hook instead to keep the library clean and to allow the clients to customize the final tls config that will be in use for connecting

Signed-off-by: amir-khassaia <amir.khassaia@gmail.com>

Signed-off-by: amir-khassaia <amir.khassaia@gmail.com>

…pport

Add client option `SetConnectionAttemptHandler` that will be called prior to dialling a broker. This enables a connection specific tls.Config to be set (providing better support for proxies and tls with multiple brokers). In addition a new example has been added that demonstrates how to connect via a proxy (using SNI).

Redact password in Stringer of packets.ConnectPacket

… Also reduce noise from tests.

Ref issue #501

Handle connection loss during call to Disconnect() (including test)