Add raw data getter on `Message`

[freya022]

General Troubleshooting

• I have checked for similar issues on the Issue-tracker.
• I have updated to the latest JDA version
• I have checked the branches or the maintainers' PRs for upcoming features.

Feature Request

JDA could have a way to optionally store the raw data of each message, similar to JDABuilder#setEventPassthrough(boolean) and GenericEvent#getRawData().

Example Use-Case

public void onGetRawMessage(MessageContextInteractionEvent event) {
    final var rawJson = event.getTarget().getRawData();

    // reply JSON in a file
}

[MinnDevelopment]

This would duplicate the size of each message object, unless there is a very good reason to store these json objects, I don't see this as a valuable feature.

[freya022]

I don't see much harm considering this would be a conditional object, the current alternative is to enable event passthrough, meaning even more data being saved for a single feature, then you'd have to correctly traverse the payload.

This would be useful for debugging purposes, even if it's likely going to be used by lib devs. I can also see it useful for transcript tools, if you send them the raw message, then that tool can be updated and new content would be shown.

@DV8FromTheWorld originally requested it, maybe he can describe his use case better (message)