[NUI] Adding VertexBuffer to replace PropertyBuffer (#1983)

* [NUI] Adding VertexBuffer to replace PropertyBuffer

Native PropertyBuffer has been renamed to VertexBuffer.
Creating a new object to mirror this name change.

Changed SetData API to take an array of structs, and create
an unmanaged buffer before passing it to native side.

Signed-off-by: David Steele <david.steele@samsung.com>
* Update src/Tizen.NUI/src/public/Geometry.cs

Co-authored-by: Marcin Macias <40991900+m-macias@users.noreply.github.com>
* Update src/Tizen.NUI/src/public/VertexBuffer.cs

Co-authored-by: Marcin Macias <40991900+m-macias@users.noreply.github.com>
* Update VertexBuffer.cs

Fixed the tizen version in the documentation

* Update Geometry.cs

Changed if() throw style.

Co-authored-by: Marcin Macias <40991900+m-macias@users.noreply.github.com>
Co-authored-by: Adeel Kazmi <adeel.kazmi@samsung.com>