Let `last_insert_id` optional and flexible. #4449

Job	Run time
Clippy	1m 26s
Examples (examples/actix_example)	2m 34s
Init	8s
Examples (examples/axum_example)	2m 34s
Rustfmt	17s
Unit Test	3m 18s
Examples (examples/basic)	1m 6s
Examples (examples/graphql_example)	2m 25s
Examples (examples/jsonrpsee_example)	2m 40s
Examples (examples/poem_example)	2m 31s
Examples (examples/proxy_gluesql_example)	1m 0s
Examples (examples/rocket_example)	3m 6s
Examples (examples/rocket_okapi_example)	3m 14s
Examples (examples/salvo_example)	2m 43s
Examples (examples/seaography_example)	2m 25s
Examples (examples/tonic_example)	2m 25s
Compile MySQL (actix, native-tls)	1m 47s
Compile PostgreSQL (tokio, native-tls)	1m 8s
Compile SQLite (async-std, native-tls)	2m 11s
Compile MySQL (actix, rustls)	2m 17s
Compile PostgreSQL (tokio, rustls)	1m 51s
Compile SQLite (async-std, rustls)	2m 5s
CLI	0s
Issues Matrix	0s
Issues	0s
Postgres	0s
SQLite	0s
MySQL	0s
MariaDB	0s
	45m 11s

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