spine runtime support for qt qml with spine-cpp 3.x

thanks for spine-qml

screenshot:

currently support:

• real time timescale
• real time fps
• real time animation mixing
• real time skin setting
• real time animation setting
• real time skeleton scaling(extractly a global scale of <scaleX, scaleY>)
• async loading
• debug bones
• debug slots
• shared image texture
• clipping effect
• full stack multithread support
• window, linux, arm/arm64 cross compile project handle
• support realtime customized blend color on rgba/gray channel
• light control

todo:

• deug vertices
• VertexEffect
• audio trigger
• prealphamultiply blending support
• astc compressed texture support