Update IR to either use import instructions directly from generated schema or use Custom resource handling (to be implemented)

### Description
IR/Imports should accept `CUSTOM<WHATEVER IT WAS> as a resource type and use separate handling from the schema to translate these resources in the stack.

### Depends On
Schema defined in #4 

### Steps
1. Pretend I wrote something real.

### Acceptance Criteria
1. Passing unit tests that prove routing works