Allow finding importId of a re-export

**Is your feature request related to a problem? Please describe.**

In Paka, a doc extraction utility, when looking at re-exports, we need to know if they are from external packages or not. To achieve this we look at the import ID. This information is not available on the result of `getExportedDeclarations`.

https://github.com/dsherret/ts-morph/blob/3dd5c72a48a7a5852cf5f995126b8cc12567ee86/packages/ts-morph/src/compiler/ast/base/ModuledNode.ts#L363

```
export { foo } from 'abc'
export { foo as bar } from 'abc2'
export * as qux from 'abc3'
```

**Describe the solution you'd like**

Not sure. Only way I see is changing the map value type. Instead of a declaration make it a wrapper type, a union of possible cases, one being `reExport` with a property like `importId`.

**Describe alternatives you've considered**

N/A

Read CONTRIBUTING.md and inspect getExportedDeclarations in packages/ts-morph/src/compiler/ast/base/ModuledNode.ts at the linked location. Use the re-export examples in the issue to understand the missing import ID information; done means callers can identify whether re-exports come from external packages while retaining the existing declaration results.

Written by the indexing model from the issue text.