Refactor OSSL_STORE_LOADER_do_all_provided() to behave like OSSL_STORE_LOADER_fetch()
Refactor OSSL_STORE_LOADER_do_all_provided() to behave like OSSL_STORE_LOADER_fetch()

This is refactored to use inner_loader_fetch() without any given name,
which is just there to ensure all decoder implementations are made
into methods, and then use ossl_method_store_do_all() to list them
all.

This also adds the internal ossl_store_loader_do_all_prefetched(),
which can be used if pre-fetching needs to be done separately from
listing all the decoder implementations, or if listing may happen
multiple times.

Reviewed-by: Matt Caswell <1fa2ef4755a9226cb9a0a4840bd89b158ac71391@openssl.org>
Reviewed-by: Tomas Mraz <2bc6038c3dfca09b2da23c8b6da8ba884dc2dcc2@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15604)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl