Add Api layer to Kernel

[patrickjaja]

https://fractal.thephpleague.com/serializers
(https://dev.to/filmineng/php-libraries-and-tools-3blf)

• Add api for available activity plugins

[patrickjaja]

https://symfony.com/bundles/NelmioApiDocBundle/current/index.html

[patrickjaja]

https://www.massiveart.com/de-de/blog/ein-setup-fuer-rest-schnittstellen-die-eleganz-von-rest-apis-mit-symfony

[patrickjaja]

https://carlalexander.ca/symfony-console-application-autowire/

[patrickjaja]

speaks json api

[patrickjaja]

https://www.freecodecamp.org/news/graphql-for-front-end-developers/amp/