chore: add full support for NLB log

[Kavindu-Dodan]

Description

Adds full field support for NLB log fields. The table below summarizes NLB field and OTel attribute it ends up (extracted from the updated documentation),

AWS Field	OpenTelemetry Field(s)
connection_time	aws.elb.connection_time
tls_handshake_time	aws.elb.tls_handshake_time
incoming_tls_alert	aws.elb.incoming_tls_alert
chosen_cert_arn	aws.elb.chosen_cert_arn
chosen_cert_serial	aws.elb.chosen_cert_serial
tls_named_group	aws.elb.tls_named_group
alpn_fe_protocol	aws.elb.alpn_fe_protocol
alpn_be_protocol	aws.elb.alpn_be_protocol
alpn_client_preference_list	aws.elb.alpn_client_preference_list
tls_connection_creation_time	aws.elb.tls_connection_creation_time

Link to tracking issue

Fixes #43757

Testing

Unit tests already covered field parsing. But I have added both samples from official AWS NLB documentation at https://docs.aws.amazon.com/elasticloadbalancing/latest/network/load-balancer-access-logs.html#access-log-entry-format

Documentation

Documentation updated with the new attributes