Remove no-longer-needed extraneous `go` subdirs

[aboodman]

Now that we no longer have a js implementation, we can get rid of the superfluous go dir at the root and just move everything into /noms.

Similarly, we can get rid of the go subdirinsamples`.

[arv]

What about the grapiql sample? It was pretty useful when using Noms+GraphQL ?

@rafael-atticlabs

[arv]

cc @wardn

[wardn]

looks like the graphiql sample is referencing the js implementations