Configurable tsc/tsconfig in createSource?

[lordofthelake]

Follow up on the tweet: for projects with complex requirements, loading external type definitions or in a monorepo, it would be useful to be able to set the tsconfig and/or the typescript module that will be used during the parsing (esp. for specifying references/aliases, strictness, and the module types — all things that influence the type checking).

The configuration options provided by @rollup/plugin-typescript could be an inspiration about the shape of the API.