[FR] faster bulk inserts

I've prepared a branch providing a new runBulkInsert action to provide up to 3x faster bulk inserts. The only difference to runWith is it re-uses a prepared statement for binding a parameter row. Additionally, the branch contains a small, synthetic benchmark to measure the overhead of preparing a statement for each row vs. once for all rows: https://gitlab.com/michael207/sqlite-easy/-/tree/mkarg/bulk-insert

@gilmi I needed this for my (not so hobby-ish) hobby project. If you think this might be worth adding to sqlite-easy, I can open a PR. Thanks for the useful package BTW 😄