DECODER: Adjust the library context of keys in our decoders

DECODER: Adjust the library context of keys in our decoders

Because decoders are coupled with keymgmts from the same provider,
ours need to produce provider side keys the same way.  Since our
keymgmts create key data with the provider library context, so must
our decoders.

We solve with functions to adjust the library context of decoded keys,
and use them.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/13661)