decode: shuffle order of JSON trace fields for readability

decode: shuffle order of JSON trace fields for readability

Use a similar order of JSON trace fields as other modes of annotation
output do. This increases readability for humans by moving timestamps
and decoder IDs to the left, and keeping the annotation text at the
right hand side with nothing else following it, and at a constant text
position (somewhat, depending on how timing numbers align, and how
several annotation rows interleave).