Android: Remove self-implemented SDK Manager frontend and refer to Android Studio

When around 3 Years ago the Java-based Android SDK manager was discontinued in favor of the current SDK Manager in Android Studio, we were left with a command-line based version of the sdkmanager.

We thought it would be uncool to depend on Android Studio and therefore created a graphical front-end for the command-line based sdkmanager.

That sdkmanager produces semi-human readable and not-so machine-readable output with formatting and logic that evolves across versions. Output looks like this:

ndk;20.1.5948944
    Description:        NDK (Side by side) 20.1.5948944
    Version:            20.1.5948944
    Dependencies:
        patcher;v4

patcher;v4
    Description:        SDK Patch Applier v4
    Version:            1

platform-tools
    Description:        Android SDK Platform-Tools
    Version:            29.0.5

platforms;android-10
    Description:        Android SDK Platform 10
    Version:            2

In the last SDK versions, quite a Maintenance back-log accumulated which I don't see being possibly tackled with the current man power. I suggest we back-off from that approach and instead depend on the SDK manager of Android Studio.

Qt Creator's Android Sdk Manager:

Android Studio's Sdk Manager: