feat(storage): avoid using box dyn for storage table merge sort

[wenym1]

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What's changed and what's your intention?

Previously in the merge sort of storage table, we use a trait NodePeek and use Box<dyn NodePeek> to hold it. Under this implementation, we will have to create a Box for each row, and have to do dynamic dispatch each time we call its method.

However, the use of Box<dyn ...> is unnecessary. In our usage, all types can be statically determined. Therefore, in this PR, we will change to use generic type with static dispatch. The code can compile.

Checklist

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