Enable Android build creation

[mariogmarq]

Since the objective of this project is enable the usage of FLEX for Android, this PR enables the build to be used in Android. A brief description of the PR done by copilot is provided:

This pull request migrates the lib module from a plain JVM library to an Android-compatible library, updating the build configuration, dependencies, and publishing setup accordingly. The changes modernize the build by adopting Android Gradle conventions, updating plugin and dependency management, and adding Android-specific configurations.

Build system migration and Android support:

• Converted the lib module to use the Android Library plugin, added an android block with appropriate SDK versions, namespace, build types, and test options, and replaced the java-library plugin. Also added a minimal AndroidManifest.xml required for Android libraries. [1] [2]
• Updated plugin and dependency management in gradle/libs.versions.toml to include Android and Kotlin plugins, and adjusted library aliases for clarity and consistency.

Dependency and compatibility updates:

• Added kotlinx-coroutines-android to support coroutines on Android, and updated the Commons Math dependency alias. [1] [2]
• Configured Java and Kotlin toolchains to use Java 21 for consistency across environments.

Build and publishing enhancements:

• Switched to the maven-publish plugin and configured publishing for the Android library, including sources JAR for the release variant and publishing to the local Maven repository. [1] [2]
• Updated JaCoCo code coverage configuration to work with the Android library structure and generate both XML and HTML reports.

Project-wide repository management:

• Added centralized plugin management and dependency resolution in settings.gradle.kts, ensuring all plugins and dependencies are resolved from google() and mavenCentral().