[TASK] Remove helhum/class-alias-loader in favor of typo3/class-alias-loader

The package helhum/class-alias-loader has been ported to TYPO3 namespace
and been released as official TYPO3 package.

This change incorporates compatibility with the old package, e.g. old config
will still be supported with a warning message to change the configuration.

Resolves: #70432
Releases: master
Change-Id: I489f3a8655d9f899cd43d2eaac609c6ad8732521
Reviewed-on: http://review.typo3.org/43852


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>