Refactor and decouple Android Sdk tools from Android Apk

[silbinarywolf]

Description

const android_tools = android.Tools.create(b, .{
    .api_level = .android15,
    .build_tools_version = "35.0.1",
    .ndk_version = "29.0.13113456",
});
const apk = android.APK.create(b, android_tools);

I propose that we split out api_level and ndk_version into something like:

const android_sdk: android.Sdk = android.Sdk.create(b, .{}); // <- Second parameter will likely be an empty struct but we'll add options later if need be.
const apk = android_sdk.createApk(b, .{
    // .api_level = .android15, // <- Maybe even possibly deprecate and just use the `Target.Query.android_api_level`
    .build_tools_version = "35.0.1",
    .ndk_version = "29.0.13113456",
});

From there, it would be nice to add additional machinery like being able to invoke commands like sdkmanager via the newly created android.Sdk through Zig to avoid needing to think about setting up environment variables like $ANDROID_HOME and $JDK_PATH.