UTIL_cmp_timeframe(): improve workaround for deprecations in OpenSSL 4.0

[DDvO]

This is a follow-up on #70.

Finally, the related OpenSSL issue has been discussed further, just before the v 4.0 code freeze deadline.
The outcome was not exactly what I suggested, but at least here is an improved workaround for the deprecation of X509_cmp_timeframe() and X509_cmp_time().

[Copilot]

Pull request overview

This PR improves the workaround for OpenSSL 4.0 API deprecations by implementing a cleaner solution for time comparison. Instead of the previous workaround that created dummy X509 certificates, the new implementation directly converts ASN1_TIME to POSIX time using OpenSSL 4.0's new OPENSSL_tm_to_posix() function. The changes consolidate the code by removing the intermediate OpenSSL 3.0-4.0 branch and updating documentation to clarify behavior with invalid times.

Changes:

• Implemented new helper functions ASN1_TIME_to_posix() and X509_cmp_time_new() for OpenSSL 4.0+
• Removed the old workaround using dummy X509 certificates for OpenSSL 4.0
• Updated documentation to clarify that null or invalid times are not checked

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/libsecutils/src/credentials/cert.c	Implements new time comparison functions for OpenSSL 4.0+ and updates UTIL_cmp_timeframe to use unified logic
src/libsecutils/include/secutils/credentials/cert.h	Updates documentation comment to clarify behavior with invalid times

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

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