Remove legacy api support.

[kailuo]

There's one minor update to the parameters in creating and modifying article method: Previously:

curl -X POST http://127.0.0.1:8086/v0/planets/my/999BB908-B79A-4C89-8DA6-1339BDFCE03E/articles \
  -F "attachment=@example.jpeg" \
  -F "title=title" \
  -F "content=content"

Now:

curl -X POST http://127.0.0.1:8086/v0/planets/my/999BB908-B79A-4C89-8DA6-1339BDFCE03E/articles \
  -F "attachments[0]=@example.jpeg" \
  -F "title=title" \
  -F "content=content"

[livid]

There's one minor update to the parameters in creating and modifying article method: Previously:

curl -X POST http://127.0.0.1:8086/v0/planets/my/999BB908-B79A-4C89-8DA6-1339BDFCE03E/articles \
  -F "attachment=@example.jpeg" \
  -F "title=title" \
  -F "content=content"

Now:

curl -X POST http://127.0.0.1:8086/v0/planets/my/999BB908-B79A-4C89-8DA6-1339BDFCE03E/articles \
  -F "attachments[0]=@example.jpeg" \
  -F "title=title" \
  -F "content=content"

If possible, I hope the code can support both attachment and attachments, so the existing clients (if any) do not need to update.

[kailuo]

Hmm, should be possible, let me take a look.