Support INSERT statements in migration scripts

[RoryQ]

Currently wrench only supports partitioned DML migration files. But this excludes INSERT statements which is useful for seeding databases with static data.

[KaffeMyers]

I see no discussion in here and an PR that was closed down.

I'm pretty much in need of it as I use it for my migration ci process and right off the bat needed to recreate a table (rename primary key) but retain the data, which I find no real option on how to handle in a simple manner without this feature.

Is it not a considered feature improvement?