@rtsketo: Modernize build & sample app, plus logging sink upgrades
- Preserve ihsanbal pretty formatting while honoring Android log priorities (DEBUG color) without a custom logger.
- Add LogSink/BatchingSink to batch whole request/response blocks, preventing interleaved logs and enabling forwarding to LogQueue.
- Simplify response layout (single status line + spacer + body) and skip blank lines to avoid Logcat “identical” collapses.
- Fix Kotlin 1.3 build issues (plugin order, trailing comma) and allow group/version overrides for JitPack.
- Update README with sink usage and JitPack coordinates.
- Modernize Gradle/AGP/Kotlin & update AndroidX/Retrofit/RxJava/OkHttp/Okio/Dagger/LeakCanary.
- Replace Kotlin synthetics with ViewBinding in the sample app.
- Migrate sample app to RxJava3/Retrofit3 & fix the PATCH endpoint.
- Add error handling to sample app requests to avoid crashes on HTTP errors.
- Use MediaStore + SAF for download/upload so the demo works on Android 10+.