Put known hashes with unkown strings in additional fields

[LeagueSandboxBot]

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Beep, boop, I'm a bot! This issue was created by @moonshadow565 in #content-serializer.

[MythicManiac]

Some clarification on this? @moonshadow565

[moonshadow565]

Currently some hashes are missing but their values are enough self descriptive to be stored under proper key in serialized content.
They could be moved to third field (other than Values and UNKNOWN_HASHES).

[MythicManiac]

You can add them to the conversion map, and update the conversion map later if we do find their proper value. That's what the content format version metadata is for in the end, as that can be used to migrate older versions to newer or the other way around. So add whatever hashes you have in mind to the conversion map and then bump the version.