The "include" directive should be able to include multiple files if
given a filename mask.

Completes remaining changes introduced in da4ffd8.

Closes: https://github.com/nginx/nginx/issues/1165

Check for OCSP status was missed in 581cf2267, resulting
in a broken validation.

Reported by Mufeed VH of Winfunc Research.

When configured, it enables Multipath TCP support on a listen socket.
As of now it works on Linux starting with Linux 5.6 and glibc 2.32,
where it is enabled with an IPPROTO_MPTCP socket(2) protocol.

To avoid EADDRINUSE errors in bind() and listen() when transitioning
between sockets with different protocols, SO_REUSEPORT is set on both
sockets.  See f7f1607bf for potential implications.

Based on previous work by Maxime Dourov and Anthony Doeraene.

Validation is rewritten to follow RFC 3986 host syntax, based on
ngx_http_parse_request_line().  The following is now rejected:
- the rest of gen-delims "#", "?", "@", "[", "]"
- other unwise delims <">, "<", ">", "\", "^", "`', "{", "|", "}"
- IP literals with a trailing dot, missing closing bracket, or pct-encoded
- a port subcomponent with invalid values
- characters in upper half

The function interface is changed to follow a common approach
to other functions used to setup SSL_CTX, with an exception of
"ngx_conf_t *cf" since it is not bound to nginx configuration.

This is required to report and propagate SSL_CTX_set_ex_data()
errors, as reminded by Coverity (CID 1668589).

Similar to map's volatile parameter, creates a non-cacheable geo variable.

Variables contain the IANA name of the signature scheme[1] used to sign
the TLS handshake.

Variables are only meaningful when using OpenSSL 3.5 and above, with older
versions they are empty.  Moreover, since this data isn't stored in a
serialized session, variables are only available for new sessions.

[1] https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml

Requested by willmafh.