This patch addresses #1514, adds the ability to fetch DN of the root
ca that was in the chain when client certificate was verified during SSL
handshake.

This is a simple cleanup that moves OCSP related code to a dedicated
file instead of interlacing it in some pure ssl connection code.

The ca-ignore-err and crt-ignore-err directives are now able to use the
openssl X509_V_ERR constant names instead of the numerical values.

This allow a configuration to survive an OpenSSL upgrade, because the
numerical ID can change between versions. For example
X509_V_ERR_INVALID_CA was 24 in OpenSSL 1 and is 79 in OpenSSL 3.

The list of errors must be updated when a new major OpenSSL version is
released.

To be able to provide JA3 compatible TLS Fingerprints we need to expose
all Client Hello captured data using fetchers. Patch provides new
and modifies existing fetchers to add ability to filter out GREASE values:
- ssl_fc_cipherlist_*
- ssl_fc_ecformats_bin
- ssl_fc_eclist_bin
- ssl_fc_extlist_bin
- ssl_fc_protocol_hello_id

openssl_version_parser() parse a string in the OpenSSL version format
which is documented here:

https://www.openssl.org/docs/man1.1.1/man3/OPENSSL_VERSION_NUMBER.html

The function returns an unsigned int that could be used for comparing
openssl versions.

Most of the SSL sample fetches related to the client certificate were
based on the SSL_get_peer_certificate function which returns NULL when
the verification process failed. This made it impossible to use those
fetches in a log format since they would always be empty.

The patch adds a reference to the X509 object representing the client
certificate in the SSL structure and makes use of this reference in the
fetches.

The reference can only be obtained in ssl_sock_bind_verifycbk which
means that in case of an SSL error occurring before the verification
process ("no shared cipher" for instance, which happens while processing
the Client Hello), we won't ever start the verification process and it
will be impossible to get information about the client certificate.

This patch also allows most of the ssl_c_XXX fetches to return a usable
value in case of connection failure (because of a verification error for
instance) by making the "conn->flags & CO_FL_WAIT_XPRT" test (which
requires a connection to be established) less strict.

Thanks to this patch, a log-format such as the following should return
usable information in case of an error occurring during the verification
process :
    log-format "DN=%{+Q}[ssl_c_s_dn] serial=%[ssl_c_serial,hex] \
                hash=%[ssl_c_sha1,hex]"

It should answer to GitHub issue #693.

Just added buf-t and openssl-compat for the missing types that appear
in the prototypes.