Support PHP 8.5

[sukhwinder33445]

PHP 8.4 changes:

• Function parameters that are null by default must be declared nullable.

Other changes:

• Remove unused patches (the patched library is no longer in use).
• Cleanup phpstan baseline.

resolves #78

[BastianLedererIcinga]

The changes look good, everything should be fine once the issue with the dependencies is resolved.

[sukhwinder33445]

The generation of some PDF fails, and the logs point to errors in the code related to wikimedia/less. I will test it again once Icinga/icingaweb2#5457 is ready.

[sukhwinder33445]

To make this branch ready for merging, the react/promise upgrade changes have been moved to a separate PR #84

[sukhwinder33445]

karriere/pdf-merge:^3.4 does not support PHP 8.2 and 8.5 simultaneously, which leads to failing tests.

We could consider replacing it with sinanbekar/pdf-merger. However, currently PDFs cannot be generated because support for wikimedia/less.php version 5.4.0 is still missing. I will test it again as soon as it is ready.

[sukhwinder33445]

I disabled the deprecation warning and tested sinanbekar/pdf-merger. Unfortunately, it is not compatible. I will try some other packages later.

[sukhwinder33445]

Tested with the previously replaced lib iio/libmergepdf with applying this patch, and it works as expected. On PHP 8.4 and 8.5, it works when deprecation warnings are disabled.

@nilmerg if there is no important reason for the replacement, we could switch back to iio/libmergepdf.

[lippserd]

Please merge the two commits that are solely for cleaning up the dependency replacement made in #77. And please rephrase the commit message and description to clarify the intent:

Cleanup leftovers from dependency replacement

bc4d059 replaced dependencies but left outdated code, addressed here:

- Catch `Throwable` instead of removed `WebSocket\ConnectionException`
- Remove patch for replaced library

Please always use short commit hashes in commit descriptions instead of GitHub PR numbers, as these have no value outside of GitHub. And please do not use bullet points if there is only one point.

Please also adjust the PR description. The only changes required to support PHP 8.5 are now the fix for implicit nullable type declarations, right? I'm also not entirely sure if it makes sense to require the missing react/child-process issue, as it requires a PR in icinga-php-thirdparty that has not yet been merged. So why is the issue resolved in the first place? If this is really a strict requirement, please require the icinga-php-thirdparty PR or remove it.