[PATCH] Update sources to support OpenSSL 4

[PATCH] Update sources to support OpenSSL 4

OpenSSL 4 now uses const in logical cases across its X.509 API; this
patch updates Qt's TLS backend to compile against both 3.x and 4.x.

To do this QT_OPENSSL4_CONST macro (expands to `const` on OpenSSL >= 4,
empty otherwise) is introduced for functions which changed in OpenSSL 4.

There were pre-existing functions that were already const in OpenSSL 3
but were declared without const in Qt's wrapper layer - they have now
been fixed with plain const.

ASN1_STRING was made opaque in OpenSSL 4, so replace direct access with
use of accessor functions through the wrappers.

tst_qsslcertificate: add expected output for OpenSSL 4's slightly
different extension formatting.
tst_qsslsocket::ecdhServer: lock to TLS 1.2 as OpenSSL 4 no longer
exports DH/ECDH parameters for TLS 1.3 sessions.

Fixes: QTBUG-145221
Pick-to: 6.8
Change-Id: Ic3f7d3cf00dbcb5b4cd1a299d3608a7c694a3454
Reviewed-by: Mate Barany <mate.barany@qt.io>
Reviewed-by: Jonas Kvinge <jonas@jkvinge.net>
(cherry picked from commit e806630e694d89f567cffa9c982d1f471089ecd8)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
Gbp-Pq: Name upstream_openssl4.patch