Simplify the EVP_PKEY_XXX_fromdata_XX methods.

Simplify the EVP_PKEY_XXX_fromdata_XX methods.

The existing names such as EVP_PKEY_param_fromdata_settable were a bit
confusing since the 'param' referred to key params not OSSL_PARAM. To simplify
the interface a 'selection' parameter will be passed instead. The
changes are:

(1) EVP_PKEY_fromdata_init() replaces both EVP_PKEY_key_fromdata_init() and EVP_PKEY_param_fromdata_init().
(2) EVP_PKEY_fromdata() has an additional selection parameter.
(3) EVP_PKEY_fromdata_settable() replaces EVP_PKEY_key_fromdata_settable() and EVP_PKEY_param_fromdata_settable().
    EVP_PKEY_fromdata_settable() also uses a selection parameter.

Fixes #12989

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14076)