API Improvement: more study metadata, more ways of getting it

[Siderite]

At the moment there are two APIs for study metadata:

• HEAD https://lichess.org/api/study/{studyId}.pgn - which gets only some date information in the headers of the response for just one study, which is quite unuseful
• GET https://lichess.org/api/study/by/{username} - which gets the id, name, creation and last update times for studies of a particular user

There is a user request for more study information in the studies list: likes, members, number of chapters, numbers of moves, computer analyses and types of chapters, etc.

Proposal: an API similar to the one by username, that gets more metadata, by list of ids

[Siderite]

May I also add I am not the only one decrying a lack of study search APIs: https://lichess.org/@/CheckRaiseMate/blog/comparing-lichess-and-chessbase/fZRZfwhI https://lichess.org/forum/community-blog-discussions/ublog-fZRZfwhI?page=1