Remove gogoduck layer name

*Don't merge yet, please*
Hey @anguss00,

These changes just remove the gogoduckLayerName column from the db. This is now not needed based on your recent work, correct?

I also found a couple of other uses of the variable in JS which I think might be not needed anymore, but I wanted to check with you. I haven't tested these JS changes. :D

I just wanted to get your thoughts.