all: prepare for path-based trie storage (#26603)

This PR moves some trie-related db accessor methods to a different file, and also removes the schema type. Instead of the schema type, a string is used to distinguish between hashbased/pathbased db accessors.
This also moves some code from trie package to rawdb package.

This PR is intended to be a no-functionality-change prep PR for #25963 .

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Co-authored-by: Gary Rong <garyrong0905@gmail.com>

tests/fuzzers/stacktrie/trie_fuzzer.go

@@ -152,7 +152,7 @@ func (f *fuzzer) fuzz() int {
 		spongeB = &spongeDb{sponge: sha3.NewLegacyKeccak256()}
 		dbB     = trie.NewDatabase(rawdb.NewDatabase(spongeB))
 		trieB   = trie.NewStackTrie(func(owner common.Hash, path []byte, hash common.Hash, blob []byte) {
-			dbB.Scheme().WriteTrieNode(spongeB, owner, path, hash, blob)
+			rawdb.WriteTrieNode(spongeB, owner, path, hash, blob, dbB.Scheme())
 		})
 		vals        kvs
 		useful      bool