update to php8

[digibeuk]

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this PR updates the codebase to be compatible with php8, after this we can start to use php8 features like type hints etc.

fixes : https://github.com/S1lentium/IPTools/issues/38

[digibeuk]

thanks for the comments @simPod and @lyrixx, updates have been made

[S1lentium]

@digibeuk Thank you for PR. Unfortunately, at the moment I don't have enough time to support and check PRs. I hope this commit will not break the dependence on older versions of PHP. I'll tag this commit a bit later