Move bundled_executor_runner to sdk/bundled_executor_runner using hg mv (#621)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/621

Move bundled_executor_runner to sdk/bundled_executor_runner, using `hg move` this time. Creating this sdk folder will allow us to create more demo/example files focused on the SDK and usage.
```
hg mv ~/fbsource/fbcode/executorch/examples/bundled_executor_runner/* ~/fbsource/fbcode/executorch/examples/sdk/bundled_executor_runner

```

From D49895736

Reviewed By: tarun292

Differential Revision: D49928319

fbshipit-source-id: dc310b0dafd8c547bd7c864e5d393c350ddd018e