[!!!][FEATURE] Introduce PSR-3 Logging

TYPO3's Logging Framework (especially LogLevel and LogManager)
are not PSR-3 compatible, as it uses integers as constants
and not strings, as defined in PSR-3's interfaces.

This makes TYPO3 incompatible to use custom loggers,
or to interop with other logging systems.

The patch changes the logging API to depend on PSR-3
interfaces but strives for maximum compatibility.

Resolves: #88799
Releases: master
Change-Id: Ib41840cc87035c2323087877bac07e62c439482e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61156


Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>