Fix/php81

[Donatello-za]

Hi, I am concerned about the future of this repository and through this pull request I'm hoping to get the library up to PHP 8.1's standard and compatibility.

Some notes:

• These changes are not backwards compatible with PHP versions older than 8.1.
• The changes made with this un-merged pull request GH-43 was also implemented.
• You'll have to consider strategies for how to allow upgrades from the 2.x branch or the 3.x branch.
• Every file apart from the unit tests have been worked on. This was to fully implement strong typing and PHP 8.1 features.
• The deprecated LogFormatter class and unit tests have been removed.
• Unit Testing success is 100% and coverage is the same as before. However, the dev dependencies of the external vanilla/garden-container repository causes deprecation warnings during unit testing. To solve this, that package will also need upgrading to PHP 8.1
• Psalm analyses succeeds 100% with 0 warnings or notices.

If you end up using this pull request your welcome to squash the commits, I can also do it from this side but I'm not sure if you'd like to see the progression of the commits.

[Donatello-za]

I did notice just now that some source code formatting changes crept in due to my IDE setup. If you are not happy with it I can change those back.

[blacktek]

Hello, any idea when the pull request of Donatello-za can be accepted and the new package released with composer?

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

:white_check_mark: Donatello-za
:x: thisispiers
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