Introduce intermediate digest/MAC API and use it in the engine and provider

[Mironenko]

This PR adds the GOST_digest* and GOST_digest_ctx* APIs, providing
access to digest and MAC implementations. These APIs replace the use of
EVP_MD*/EVP_MD_CTX* APIs in provider.

An adapter is added to use the new APIs from the engine implementation,
so the major part of the new code is extensively tested with both engine
and provider tests.

The previously added standalone gost_digest adapter for the provider
is removed (the commit is reverted), as that approach resulted in large
diffs while not improving clarity.

This PR addresses several issues: resolves #502, resolves #503, resolves #505.

[Copilot]

Pull request overview

This PR introduces a new internal “intermediate” digest/MAC API (GOST_digest* + GOST_digest_ctx*) and refactors both the provider and engine paths to use it, reducing reliance on EVP_MD*/EVP_MD_CTX* in provider code while keeping ENGINE compatibility via an adapter layer.

Changes:

• Add gost_digest.* + gost_digest_ctx.* plus internal gost_digest_details.h to represent and run digest/MAC implementations via internal contexts.
• Refactor provider digest and MAC implementations to use GOST_digest_ctx_* instead of EVP digest contexts.
• Add an ENGINE adapter (gost_eng_digest*) to expose the new digest/MAC implementations through legacy EVP interfaces.

Reviewed changes

Copilot reviewed 30 out of 30 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
utils_one_level_inheritance.h	Removed legacy macro-based “inheritance” utility previously used for digest descriptors.
gost_tls12_additional_kexpimp.c	Switched include to gost_lcl.h to pick up needed digest/MAC control definitions via internal headers.
gost_prov_mac.h	New header exposing provider MAC init/deinit and algorithm list.
gost_prov_mac.c	Provider MAC refactor to GOST_digest_ctx_*; renamed MAC descriptors and added MAC init/deinit.
gost_prov_digest.c	Provider digest refactor to GOST_digest_ctx_* and new digest init/deinit flow.
gost_prov.h	Removed outdated MAC deinit declaration / MAC algorithm extern (moved to new header).
gost_prov.c	Provider init/teardown updated to call MAC init/deinit.
gost_omac_acpkm.c	Migrated ACPKM OMAC implementation from EVP_MD_CTX to GOST_digest_ctx.
gost_omac.c	Migrated OMAC implementation from EVP_MD_CTX to GOST_digest_ctx; descriptor rename/base templating updates.
gost_md2012.c	Migrated Streebog(2012) digest implementations to GOST_digest_ctx and new descriptor layout.
gost_md.c	Migrated GOST R 34.11-94 digest implementation to GOST_digest_ctx and new descriptor layout.
gost_mac.h	Removed old header that defined digest ctrl constants (now defined in gost_lcl.h).
gost_lcl.h	Switched from gost_mac.h to gost_digest.h; updated exported digest symbols; moved ctrl defines here.
gost_eng_digest_define.h	New macro-based generator for per-digest ENGINE ctrl adapter and GOST_eng_digest instances.
gost_eng_digest_define.c	New compilation unit instantiating ENGINE adapters for all supported digests/MACs.
gost_eng_digest.h	New ENGINE adapter API declarations (GOST_eng_digest_*).
gost_eng_digest.c	New ENGINE adapter implementation bridging EVP_MD to GOST_digest_ctx.
gost_eng.c	ENGINE registration updated to use GOST_eng_digest adapters instead of raw GOST_digest.
gost_digest_details.h	New internal struct definition for GOST_digest descriptors.
gost_digest_ctx.c	New internal digest context implementation (GOST_digest_ctx_*).
gost_digest_base.h	Removed obsolete “base” digest descriptor abstraction.
gost_digest_base.c	Removed obsolete “base” digest descriptor abstraction implementation.
gost_digest_3411_94.h	Removed old standalone provider digest descriptor declaration.
gost_digest_3411_94.c	Removed old standalone provider digest implementation (now in gost_md.c).
gost_digest_3411_2012.h	Removed old standalone provider digest descriptor declarations.
gost_digest_3411_2012.c	Removed old standalone provider digest implementation (now in gost_md2012.c).
gost_digest.h	Public digest API updated to new GOST_digest* / GOST_digest_ctx* entry points.
gost_digest.c	New GOST_digest_init/deinit and descriptor “base” resolution implementation.
gost_crypt.c	Migrated GOST 28147-89 MAC digests and associated ctrl logic to GOST_digest_ctx.
CMakeLists.txt	Consolidated digest sources into core; added new ENGINE adapter sources; removed gost_new_core_digest target and link usage.

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