bench crate refactor

[jmayclin]

Problem:

Too much "magic". Abstraction over library-specific structs is sometimes unavoidable, but should be minimized.

Solution:

*Connection structs should not be responsible for owning/storing session tickets. This would allow use to get rid of a layer of abstraction and directly impl TlsConnection on s2n_tls::connection::Connection.

This would reduce the amount of "magic" happening, which should prevent scenarios like #5305 from happening.