chore: Modernize project setup

Update dependencies, move to Gradle KTs and overall improve build and project files.

android/app/proguard-rules.pro

@@ -1,10 +1,3 @@
-# Add project specific ProGuard rules here.
-# You can control the set of applied configuration files using the
-# proguardFiles setting in build.gradle.kts.kts.
-#
-# For more details, see
-#   http://developer.android.com/guide/developing/tools/proguard.html
-
 -dontobfuscate
 
 -keep class app.revanced.** { *; }