Show difficulty rating with mods applied on score pages

[cl8n]

random thing my friend mentioned would be nice. not sure if this fits as an include for scoretransformer, was just the easiest way to get it to that page

[nanaya]

After some discussion, the attribute should be fetched through external api server instead. Similar to score rank but on its own library class (with the data either fetched through score model/transformer itself or its own json).

[peppy]

To elaborate, if we just want to get this in, maybe it's okay to go with it as-is rather than draw things out, but eventually we're going to want to use the lookup microservice as it will be required in the future.