make `Parser` generic around dialect

if we care about performance, we should stop using dynamic dispatch and make the parser generic around the dialect, with that we could make lots of these methods `const` (or drop the `Precedence` enum and just have const values on the trait) and probably improve performance significantly in general.

That would of course be a big change to the public API.

This is definitely how would implement `Parser` if I was starting now, but I think we should see some evidence that parsing SQL is a meaningful chunk of time for anyone before making a change like this.

My guess is that:
* even for quick queries, SQL parsing is <1% of query time
* making `Parser` generic and therefore dropping the restriction on `Dialect` that it has to be 'object safe' would actually only save us ~20%

If both those assumptions are right, this doesn't seem worth it unless it makes the code generally easier to reason with and work on.

_Originally posted by @samuelcolvin in https://github.com/sqlparser-rs/sqlparser-rs/issues/1379#issuecomment-2289164242_

(separate issue seems worth it for this discussion)

まず Parser、Dialect、Precedence enum を調査し、SQL パースがクエリ時間の中で意味のある割合を占めるかどうかを確認します。現在の動的ディスパッチ方式をベンチマークし、汎用的な Parser 設計と比較します。パフォーマンス上の利点についての証拠が得られ、公開 API の変更方針が確定すれば完了です。

索引モデルが issue の本文から書いたものです。