Allow ignoring unknown sigalgs and groups in the configuration

Allow ignoring unknown sigalgs and groups in the configuration

Related to #20789

Signature algorithms and groups in the configuration that are
preceded with ? character and are unknown to libssl are just ignored.
The handling for them is similar to handling of ciphers.
I.e., there should be a failure only in case the configuration produces
no valid sigalgs or groups.

Also ignore duplicate sigalgs and groups as such confiuration errors
should not be fatal.

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/23050)