[NUI] Add public types to replace nested types of Components.Button (#1810)

[NUI] Add public types to replace nested types of Components.Button (#1810)

To replace nested types (CA1034 of StyleCop), the following is added.
- class ClickedEventArgs
- event EventHandler<ClickedEventArgs> in Button class

The followings are deprecated.
- class ClickEventArgs in Button class
- event EventHandler<ClickEventArgs> in Button class

Co-authored-by: Jaehyun Cho <jae_hyun.cho@samsung.com>