Add PHP 8.5 support

[JanTvrdik]

Summary

• Add PHP 8.5 support following the same pattern as PHP 8.4 (commit c1c00dc)
• Add extensions/8.5 directory with symlinks to core extensions
• Update CI workflow to build and test PHP 8.5 images
• Update Makefile with PHP 8.5 test targets

Test plan

• Verify PHP 8.5 images build successfully
• Run test suite against PHP 8.5 images
• Verify extensions work correctly on PHP 8.5

[mistraloz]

issue: Blackfire updated the documentation : they said that is supported including 8.4 and 8.5

[mistraloz]

issue: That is no more true https://support.blackfire.platform.sh/hc/en-us/articles/4740726712082-PHP-versions-Platforms-support

[mistraloz]

Thx a lot for your PR. Please may you check the CI and fix it ?
On Dockerfile.slim.apache:52
52 | >>> RUN apt update
53 | >>> && apt install -y --no-install-recommends
54 | >>> php${PHP_VERSION}-cli
55 | >>> php${PHP_VERSION}-curl
56 | >>> php${PHP_VERSION}-mbstring
57 | >>> php${PHP_VERSION}-opcache
58 | >>> php${PHP_VERSION}-readline
59 | >>> php${PHP_VERSION}-xml
60 | >>> php${PHP_VERSION}-zip \

From 8.5, opcache is a builtin feature so php${PHP_VERSION}-opcache is no more required.
I suggest something like that :

RUN OPCACHE_PACKAGE="" \
    && if [ "${PHP_VERSION}" != "8.5" ]; then \
        OPCACHE_PACKAGE="php${PHP_VERSION}-opcache"; \
    fi \
    \
    && apt update \
           php${PHP_VERSION}-zip \
           ${OPCACHE_PACKAGE} \