CLEANUP: listeners: do not include openssl-compat

CLEANUP: listeners: do not include openssl-compat

Listeners only include openssl-compat to provide the SSL_CTX type to
use as two pointers to contexts, and to detect if NPN, ALPN, and cipher
suites are supported, and save up to 5 pointers in the ssl_bind_conf
struct if not supported. This is pointless, as these ones have all been
supported for about a decade, and including this file comes with a long
dependency chain that impacts lots of other files. The initial_ctx and
default_ctx can perfectly remain void* instead of SSL_CTX*.