Autofocus on getstage.app/link input

[NiklasBuchfink]

Set focus automatically to the input field for link configuration. Please check in onboarding process.

Use autofocus attribute

[NiklasBuchfink]

@felixhaeberle @NilsJacobsen pls check if this can be closed 😉

[felixhaeberle]

This broke the CI system and is not tested yet. Will test it tomorrow.