Add ability to override the bundle id of launched app or login item

[fwal]

Hello! 👋🏻

This is a suggestion on how to enable further customization of the project setup to cover more advanced use-cases. Essentially this PR will enable setting the bundle id that is set as login item by configuring a LLTargetBundleId post in Info.plist.

This can be utilized in a number of ways:

• This will allow the use of the api from outside the bundle that contains the login item, for example there could be a main application that contains another application that should be the one automatically started.
• This also allows skipping the use of the helper app altogether and pointing to a custom login application but still makes use of the api for toggling the application.

[sindresorhus]

Sorry. I completely missed this pull request. I'm unfortunately not going to accept this. Every change is a risky change at this point and Apple has made this package moot in macOS 13. https://github.com/sindresorhus/LaunchAtLogin/issues/76