Expose migration builder impl, make node-pg-migrate can used as a schema builder library

[wenerme]

Description

I hope I can just generate sql by using node-pg-migrate's DSL, I think node-pg-migrate should seperate the build & execution part.

like this #651 , I'd like to make a standalone js app, means no fs access.

I hope I can execue the migration by kysely (https://kysely.dev/docs/migrations ), just generate sql by node-pg-migrate.

Suggested solution

Expose the builder impl (e.g. createMigrationBuilder), the final migration is just like interface Migration {up():MaybePromise<any>, down?:()=>MaybePromise<any>}, the migration set is Record<string,Migration>, the runner/execution to decide which migrations should execute.

Alternative

No response

Additional context

No response