Apply Spotless to YAML files

[mpkorstanje]

Currently we don't apply Spotless to YAML files leading to some drift in formatting as highlighted in #5816. While this PR also shows some other drifters, I don't think there are enough of them to warrant any automation.

Deliverables

• Configure Spotless to format YAML files.

[mpkorstanje]

@BaumiCoder I'm having some difficulty assigning this issue to you through Githubs UI. For now consider this issue assigned to you.

[marcphilipp]

IIRC GitHub requires a comment on the issue from a user before it let's you assign it to them.

[BaumiCoder]

Okay, here is a comment. Can it now be assigned to me?