Introducing a patch that lifts some run-as restrictions

[ChrysoliteAzalea]

Hello everyone! I propose patching run-as to remove some restrictions (specifically, allows running as system apps and non-debuggable apps).

Removing restrictions in the run-as utility by patching the utility itself is also a far cleaner way to enhance its usefulness than tampering with the package list, and is less likely to introduce problems.

[ChrysoliteAzalea]

I've decided to keep the "reject system apps" restriction, because run-as is accessible not only to root, but to shell (ADB), and lifting the UID restriction can potentially allow running commands under privileged users (such as root or system) with ADB.