Update tutorial to reference dummy model instead of MV2 (#1059)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/1059

SDK Tutorial moved to using an inline model instead of mv2 for cleaner imports
- This diff aligns the rest of the tutorial to the inline model

**Aside:**
- Adds a link to bundled_program for users to reference
- Mocks outputs for website (to compensate for runtime steps occurring outside of notebook)

Reviewed By: Gasoonjia

Differential Revision: D50515890

fbshipit-source-id: 0139e9953d6ef8bd23036917d6219b2d8b0b3e08