change(state): Move format upgrades to separate modules

[arya2]

Scheduling

This change is blocked by #7392.

Motivation

This PR moves the tree deduplication into a separate module ahead of adding more upgrades and state validity checks.

Depends On: #7379.

Solution

• Moves upgrade to separate file

Review

Anyone can review.

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[teor2345]

Just noting that this code movement PR will conflict with PR #7392, which is a low priority security fix.

Refactors are usually lower priority than fixes, so let's mark this as optional?
(Neither of them are on the critical path to getting RPCs working.)

[arya2]

Just noting that this code movement PR will conflict with PR #7392, which is a low priority security fix.

I think the changes for adding subtrees from existing blocks will conflict with that anyway?