[TASK] Throw exception when CLI command is added twice

If two extensions register the same command, the "last one"
wins currently.

The patch throws an exception if there is already a name
or alias with this command name.

Resolves: #79590
Releases: master
Change-Id: Iaafb97d88455077ab60689c32dda0580c47e0b47
Reviewed-on: https://review.typo3.org/51316


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>