This adds the following four new high-level entrypoints:

- `interpretExpr`
- `interpretExprWithSettings`
- `fromExpr`
- `fromExprWithSettings`

… as well as several new utilities for running each phase one at a
time, respecting `InputSettings`:

- `parseWithSettings`
- `resolveWithSettings`
- `typecheckWithSettings`
- `expectWithSettings`
- `normalizeWithSettings`

This also refactors the other utilities to use those new phase-based
settings.

The motivation behind this change is to make it easier for people
to work with raw `Expr`s, so that people don't need to craft strings
when trying to assemble ASTs to interpret like in this issue:

https://stackoverflow.com/questions/77037023/is-there-an-elegant-way-to-override-dhall-records-in-haskell