API health and database counts

curl --request GET \
  --url https://mkk.celebi.me/api/health

{
  "status": "ok",
  "documents": 123,
  "funds": 123,
  "sections": 123,
  "line_items": 123,
  "line_item_values": 123,
  "portfolio_entries": 123,
  "portfolio_rows": 123
}