Add --forward-port and --reverse-port via ADB on Android

[timrid]

This PR adds the possibility to forward/reverse a port to an Android app via ADB.

I needed the forwarding/reversing for adding debug capabilitys to Android in #2351. But now I also have another use case, where I want to connect the android app to a REST-Server running on my host system. So I though it would be generally a useful feature for briefcase.

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[mhsmith]

Thanks, this is very good. Obviously it only works when the app is launched via Briefcase, but like --shutdown-on-exit, it could still be useful for all kinds of scripted situations.

[timrid]

Obviously it only works when the app is launched via Briefcase, but like --shutdown-on-exit, it could still be useful for all kinds of scripted situations.

Yes, that was the intention of these options.

If you need a permanent connection to the Android device, you would have to use ADB manually. For this it would also be practical to have access to the ADB downloaded by briefcase. E.g. via a new command briefcase tool adb. Then you would use briefcase tool adb forward tcp:5555 tcp:6666 to have a permanent connection. And to close this connection you can use briefcase tool adb forward tcp:5555 --remove. This would give you complete freedom to do every configuration with ADB without searching for the path where ADB is downloaded or manually downloading ADB. But this would be a different feature.

[mhsmith]

There are some similar ideas in #747.