Add attributes on the formatter level

@larowlan if you're fine with the proposal, we'll start implementing this as submodule via MR.

Yes, please make this feature happen. Adding attributes to link fields is horrible on frontend.

Element class formatter does this too I think

I'm happy with a sub-module, but we'd have to be mindful about how we merge values from the formatter with user supplied values.

Perhaps we need options 'overrride user options' or 'user options override defaults'

Thanks for the feedback @larowlan that's wonderful news!

Yes I think one of the key benefits is to have that control in one module. For the beginning, I'd say we should simply merge and unify them, not overriding anything. For the future we should then see, if there are cases where overriding into one or the other direction makes sense as an option? (YAGNI)

It's planned to start here soon! :)