[FEATURE]: Support setting collation of columns

### Describe want to want

Another fun Postgres feature! Let's say you're using [fractional indexing](https://observablehq.com/@dgreensp/implementing-fractional-indexing) and want to sort strings in a particular way that has nothing to do with their ordering in English or any other language, but with how they'd compare by codepoints, like ASCII strings. You could use `COLLATE "C"` to do that.

This would be an addition to the `text()` type in the schema builder.