put bundled program under executorch/sdk (#1014)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/1014

This stack aims to restructure bundledprogram codebase. The target structure should be like D49605947.

This diff moves bundled program codebase from executorch/ to executorch/sdk/

Reviewed By: tarun292

Differential Revision: D50422728

fbshipit-source-id: 6f51b726bf0f883a2798a400e1dd16ab8f3b84cc