Rework dbt-sugar ENTIRELY... to use dbt v1 API

[bastienboutonnet]

The time has come! dbt-core is now v1.

This project decided to not use any of the dbt internals in early stages because we didn't know how stable things would be.

With the v1 guarantee, now, we should be able to identify a bunch of places where we can retire our in-house, potentially brittle logic and move along with dbt a little bit more hand in hand.

Needless to say, this is going to be a hell of a rework, so we'll link more specific unit of changes to this issue so that we can keep things traceable.