`bootstrap.sh` refactor (#28809)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28809
### Summary
This PR adds the interactive mode to `bootstrap.sh`. Instead of passing the credential information from command parameters(`-t`,`-p`), we're going to ask the user enter that information and save it to a config file, such that next time you don't have to enter again. So all you need now, is one line command
```shell
./bootstrap
```
### Test Plan
- TestApp.ipa can be installed on any devices
- Don't break CI jobs
Test Plan: Imported from OSS
Differential Revision: D18194032
Pulled By: xta0
fbshipit-source-id: a416ef7f13fa565e2c10bb55f94a8ce994b4e869
