Support PHP 8.4/8.5

[BastianLedererIcinga]

Changes that had to be addressed

PHP 8.3 -> PHP 8.4

Migration docs: https://www.php.net/manual/en/migration84

• Function parameters that are null by default must be declared nullable.
• Changing the value of session.sid_bits_per_character is deprecated.

PHP 8.4 -> PHP 8.5

Migration Docs: https://www.php.net/manual/en/migration85

• curl_close() is deprecated in PHP 8.5, curl handles are instead freed automatically.
• Driver specific PDO constants are deprecated this affects some MySQL driver constants,
  instead of PDO::SQL<constant_name> use Pdo\Mysql::<constant_name>.
• ReflectionProperty::setAccessible has been deprecated, but did not have any effect since PHP 8.1.
• Float to int casts, where the original value can't be represented as an integer will emit a warning. floor() must be used before the cast to achieve the previous behavior without a warning.
• The backtick operator is deprecated, shell_exec() must be used instead.
• Using null as an array offset or passing it to array_key_exists it deprecated, an empty string must be used instead

resolves: #5269
resolves: #5450

[nilmerg]

Please make absolutely sure we're dealing with floats here. My feeling is that this change isn't strictly necessary since we're dealing with timestamps and those are usually a result of time() or DateTime->getTimestamp(), in which case it's always an int.

There are probably other cases as well, I won't comment on each one. Please review them again and ensure on your own that you don't floor unnecessarily. It's maybe also an option to prevent decimals in the first place, given the calls are internal only. Though, an exception is Benchmark, as it already floored its timestamp previously so there's no problem to do it still.

[sukhwinder33445]

The change has been reversed.

[nilmerg]

Also, the changes to the monitoring module seem implausible to be complete. You already acknowledged in person that you didn't test it yet since you don't have the IDO enabled/configured. Please talk to @lippserd whether that's necessary to begin with.

[nilmerg]

The fact that 730af4c doesn't conditionally call setAccessible still, means that this only works on PHP >= 8.1, so this plays into the question what will happen with monitoring.

[sukhwinder33445]

LGTM 👍🏽