Feature: #96935 - New registration for linkvalidator linktype

See forge#96935

Description

The system extension linkvalidator uses so called linktypes for checking different types of links, e.g. internal or external links. All linktypes have to implement the LinktypeInterface.

This fact is now used to automatically register the linktypes, based on the interface, if autoconfigure is enabled in Services.yaml. Alternatively, one can manually tag a custom linktype with the linkvalidator.linktype tag (see section "Migration" in the breaking changelog).

Due to the autoconfiguration, the identifier has to be provided by the class directly, using the now required getIdentifier() method. When extending \TYPO3\CMS\Linkvalidator\Linktype\AbstractLinktype it's sufficient to set the $identifier class property.

Impact

linktypes are now automatically registered through the service configuration, based on the implemented interface.