OpenSSL: Remove deprecated non EVP code

[matejk]

Plenty of deprecated code is removed in #4426.

Removing non-EVP OpenSSL is a larger task that shall be handled separately.

[matejk]

Analysis

This is the umbrella tracking issue for removing deprecated non-EVP OpenSSL code. The scope overlaps with #4846 — resolving #4846 (replacing deprecated RSA/EC_KEY types with EVP_PKEY-based API) would effectively close this issue as well.

Current State

PR #4426 already removed some deprecated code. The remaining non-EVP code is the same set identified in #4846:

• RSA struct operations in RSAKeyImpl, RSACipherImpl, RSADigestEngine
• EC_KEY struct operations in ECKeyImpl, ECDSADigestEngine
• Legacy conversion functions (EVP_PKEY_get1_RSA, EVP_PKEY_get1_EC_KEY, etc.) in EVPPKey.cpp

Recommendation

Close this issue together with #4846 once the EVP migration is complete. The work is identical — this issue just tracks it from a different angle (removing deprecated code vs. replacing with modern equivalents).

[matejk]

Addressed by PR #5313 which removes all non-EVP code on the OpenSSL 3.0+ path.

RSA operations (RSA_new/free/size/generate_key_ex, RSA_public_encrypt/private_decrypt, RSA_sign/verify, PEM_read/write_bio_RSA*) and EC operations (EC_KEY_new/free/generate_key, ECDSA_sign/verify, EVP_PKEY_get1/set1_RSA/EC_KEY) are replaced with EVP_PKEY equivalents. The non-EVP code remains in #else branches for OpenSSL 1.1.x only.

Duplicate of #5296.