Audit usage of Debug `{:?}` formatting

[wwylele]

{:?} in principle should be only used for dev purpose and not in product output. For this project, it should be used in the following situation

• printing to stderr is fine
• output to website when a record (monster, item etc.) is not found for a given ID is ok
• output yet to understand property to website is temporarily ok, but should be continue investigated
• output already understood enum to website shouldn't go through Debug any more
• shouldn't be part of any url