Summary

This PR removes all compatibility code for OpenSSL versions prior to 1.1.1, significantly simplifying the codebase.

Closes #3739

Changes

CMake Requirements

• Added minimum OpenSSL version 1.1.1 to find_package() calls

Crypto Library

• Updated compile-time version check in Crypto.h to require OpenSSL 1.1.1
• OpenSSLInitializer: Removed manual thread locking callbacks (OpenSSL 1.1.0+ handles threading automatically via CRYPTO_set_locking_callback)
• CipherImpl: Simplified EVP_CIPHER_CTX handling to use pointer-based API only (removed stack allocation path)
• CipherKeyImpl: Removed version conditional around CTR/GCM/CCM cipher modes
• EVPPKey: Removed version conditional for EC key support constructor
• RSAKeyImpl: Simplified RSA_get0_key() usage (removed manual BIGNUM access)
• X509Certificate: Removed compatibility macros for ASN1_STRING_get0_data, X509_get0_notBefore/notAfter, X509_up_ref, and X509_get_signature_nid

NetSSL_OpenSSL Library

• Context: Removed all TLS method version conditionals, now uses TLS_method()/TLS_client_method()/TLS_server_method() only. Simplified ECDH initialization and security level functions
• SecureSocketImpl: Removed conditionals for TLS 1.3 session tickets and OCSP stapling. Added explicit Mutex.h include (previously transitive through OpenSSLInitializer.h)

Rationale

OpenSSL 1.1.1 reached end-of-life on 2023-09-11. All actively maintained systems should have at least this version available. The 1.1.x series introduced significant API changes that required extensive version conditionals in the codebase. Removing this legacy support:

• Reduces code complexity (~370 lines removed)
• Eliminates potential bugs in rarely-tested code paths
• Simplifies maintenance and future development
• OpenSSL 3.x is backward compatible with 1.1.1 APIs used here