Feature: #88799 - Introduced PSR-3 compatible Logging API

See Issue #88799

Description

The existing Logging API evolved pretty similar to the later established PSR-3 logging standard. There was one key difference between the standard and the TYPO3 implementation though: The log levels were represented by numbers in TYPO3 whereas PSR-3 requires the string representation.

TYPO3 therefore finally adapted to the standard and opens up for better integration with other libraries also following the standard.

Impact

The adaption was not possible without a few breaking changes to the code base. Luckily no configuration changes are necessary, hence integrators are not affected by those.