Cronvoy: Support for Network Quality Estimator (NQE)

NQE is currently supported by Cronet, and two Android Apps do use it:

- Android Google Maps for Mobile (AGMM), _quite understandable_
- Android Google Search App (AGSA)

All Android services needed to implement the "NQE feature" are in Java, part of the Android system libraries. Hence, Cronet maintains a set of Java classes wrapping invocations to these libraries, exposing the needed JNI hooks to the C++ layer.

- [```AndroidCellularSignalStrength.getSignalStrengthLevel```](https://source.chromium.org/chromium/chromium/src/+/main:net/android/java/src/org/chromium/net/AndroidCellularSignalStrength.java)
- [```AndroidNetworkLibrary.getWifiSignalLevel```](https://source.chromium.org/chromium/chromium/src/+/main:net/android/java/src/org/chromium/net/AndroidNetworkLibrary.java;l=282)
- [```AndroidNetworkLibrary.reportBadDefaultNetwork```](https://source.chromium.org/chromium/chromium/src/+/main:net/android/java/src/org/chromium/net/AndroidNetworkLibrary.java;l=446) M+
- [```NetworkActivationRequest.createMobileNetworkRequest```](https://source.chromium.org/chromium/chromium/src/+/main:net/android/java/src/org/chromium/net/NetworkActivationRequest.java): attempts to rather use the Cellular Network when WIFI is unresponsive.