Move away from elastic-array-plus 0.10 (will panic in future rust)

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Hello! I'm coming to this repo from rust-lang/rust#99389, and am making an issue for etcommon-block, etcommon-block-core, etcommon-rlp, etcommon-trie, etcommon-trie-test.

These were all crates that depend on elastic-array-plus in a way that will panic in future rust.

It looks like elastic-array-plus is just an array vec, so any array vector crate would work to replace it. https://crates.io/crates/arrayvec might be a good choice.