[ENSWEB-2180] Adding a JSON endpoint as needed by S4
[ENSWEB-2180] Adding a JSON endpoint as needed by S4

Replacement of DAS Multi.EnsemblGeneId.spine endpoint

muffato/public-plugins,Ensembl/public-plugins,Ensembl/public-plugins,muffato/public-plugins,Ensembl/public-plugins,muffato/public-plugins,muffato/public-plugins