Add sample for Drag & Drop

[MartinZikmund]

What would you like to be added:

Uno Gallery sample on using drag and drop in Uno Platfrom. https://platform.uno/docs/articles/features/pointers-keyboard-and-other-user-inputs.html#drag-and-drop

Why is this needed:

Developer samples

For which Platform:

All

[PalaniappanC]

Hi I would like to work on this, please assign this to my name

[kazo0]

Thanks @PalaniappanC! I have assigned it to you, let us know if you need any help!