s2n-quic-events: Add support for generating s2n-tls events system

[goatgoose]

Problem:

s2n-quic/s2n-quic-dc currently use an events system generated by s2n-quic-events to publish events within s2n-quic and allow users to subscribe to these events. A similar framework is desired in s2n-tls, and s2n-quic-events (to be renamed?) will be used to generate this events system as well.

Some changes are needed to be made to s2n-quic-events in order to support this, which will be tracked in this issue.

• s2n-quic-events: Generate a test events system for testing TLS-specific changes #2765
• s2n-quic-events: Add s2n-tls mode to s2n-quic-events #2766
• s2n-quic-events: Generate C bindings to publish events #2767
• s2n-quic-events: Publish s2n-quic-events #2768