Decentralize legacy_ctrl_str_to_param()

Decentralize legacy_ctrl_str_to_param()

This function did a bit too much in terms of central control, actually
more so than the legacy counterpart, where all the string processing
is done in the diverse *_pmeth.c.  Furthermore, there was no room
whatsoever for control keys that libcrypto isn't centrally aware of.

This function is changed to simply translating keys and values to
OSSL_PARAM form and then sent on their merry way to the provider
implementations through EVP_PKEY_CTX_set_params().  It translates
selected well known legacy names to their core name counterpart, and
that's as far as centralized control should extend.

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/10947)