[FEATURE] New PSR-14 events in the PageLayoutView class

Two new PSR-14 events are added in the PageLayoutView class.
Those events can be used to add content into any column of a
BackendLayout. You can use this for example to show some
content in a column without a colPos assigned.

Releases: master
Resolves: #88921
Change-Id: I9271a85220d725f5cfcdf5ce99adf871a50f6032
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61442


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Jörg Bösche <typo3@joergboesche.de>
Tested-by: Steffen Frese <steffenf14@gmail.com>
Tested-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Jörg Bösche <typo3@joergboesche.de>
Reviewed-by: Daniel Siepmann <coding@daniel-siepmann.de>
Reviewed-by: Steffen Frese <steffenf14@gmail.com>
Reviewed-by: Richard Haeser <richard@maxserv.com>