album: extend struct for /api/album/%d/data

This also includes tests against a sample response from the
https://monster-siren.hypergryph.com/api/album/1030/data endpoint.

Signed-off-by: Yonah <contrib@gensokyo.uk>

testdata/album.data.json

@@ -0,0 +1 @@
+{"code":0,"msg":"","data":{"cid":"1030","name":"Speed of Light","intro":"在无人告知方向的黑夜里，独自以光速探寻正确的道路。 \n无论看待世界是简单，亦或是复杂，大地和天空始终让开始与结束相连。 \n《Speed of Light》，通过乐调铺陈的驰放与内敛感，希望能为您呈现超脱于现实的惬意想象空间。 \n愿您掌心的小小地图一直指引着前路。像光一样前行，如企鹅物流般永不停歇。","belong":"arknights","coverUrl":"https://web.hycdn.cn/siren/pic/20210322/56cbcd1d0093d8ee8ee22bf6d68ab4a6.jpg","coverDeUrl":"https://web.hycdn.cn/siren/pic/20210322/0bf0d84e08b57acd2455b412224ba8e8.jpg","artistes":["塞壬唱片-MSR","DJ Okawari"]}}

testdata/album.detail.json

@@ -0,0 +1 @@
+{"code":0,"msg":"","data":{"cid":"1030","name":"Speed of Light","intro":"在无人告知方向的黑夜里，独自以光速探寻正确的道路。 \n无论看待世界是简单，亦或是复杂，大地和天空始终让开始与结束相连。 \n《Speed of Light》，通过乐调铺陈的驰放与内敛感，希望能为您呈现超脱于现实的惬意想象空间。 \n愿您掌心的小小地图一直指引着前路。像光一样前行，如企鹅物流般永不停歇。","belong":"arknights","coverUrl":"https://web.hycdn.cn/siren/pic/20210322/56cbcd1d0093d8ee8ee22bf6d68ab4a6.jpg","coverDeUrl":"https://web.hycdn.cn/siren/pic/20210322/0bf0d84e08b57acd2455b412224ba8e8.jpg","songs":[{"cid":"880374","name":"Speed of Light","artistes":["塞壬唱片-MSR","DJ Okawari"]},{"cid":"125012","name":"Speed of Light (Instrumental)","artistes":["DJ Okawari"]}]}}