[2.0.0-rc2] From plugin Annotation to Attributes

Hi team!
I refactored annotations with attributes in the ComponentFormatter and ComponentPerItemFormatter.
I set the field_types as entity_reference there but as I know these field_types are overridden in the ui_patterns_field_formatters_field_formatter_info_alter anyway.

Please review the MR.

Hi,

Not tested but reviewed. Ok for me. Was about to RTBC when I put 2 nitpicks comments for description.

@pdureau your opinion?

I was not expecting us to add description but only to convert existing, but that's interesting.

I have proposed my takes.

I have updated the descriptions according to suggestions.
Please review

Thanks!