[phpstan] Rebuild phpstan baseline

[rector] Kick of ligther config splits

[pre-phpunit-10] Make data providers static

getSubscribedEvents() always returns an array. Adding the return type…

[tests] Add known setup based property types

Most twig templates for form fields rely on `text.html.twig`, `grou.html.twig` or `select.html.t...

[tests] Add known void return type declarations

[PHP 8.0] Make use of PHP 8.0 features

[type-declaration] Re-run current sets for whole project on PHP 8

[PHP 7.0] Make use of up to PHP 7.0 features

[PHP 7.4] Add arrow functions and coalessce assign

[PHP 7.3] Make use of array key last/first

[type-declarations] Re-run rector rules on plugins, Report, Sms, User, Lead, Dynamic, Config bun...

[type-declarations] Re-apply rector type rules to Form, Email, Core and Campaign bundles + bump ...

[ci] make use of composer validate and make composer.lock testing simple

[PHP 8.0] Add property promotion to plugins

[PHP 8.0] Remove unused catch variable

[ci] run Rector only once, with --dry-run to fail in case of change

[PHP 7.0] Make use of coalsece

[PHP 5.6] Make use of up to PHP 5.6 features