Add view limit level parameter when show skeleton

[TaQuangTu]

I see that showing skeleton for all leaf views (views at the bottom of the view tree and have no children) is not always give a good look. I have added a field named limitToLevel: Int (default = MAX_INT) to limit the depth at which child views in the SkeletonLayout should show skeleton and stop traveling down to their child views to show skeleton. This change does not require coders to modify their code except when they need to use the parameter. I hope you will consider my tiny effort. Thank you!

[Faltenreich]

Thanks for your PR and sorry for the late response! Is this feature still required and if so, could you explain one simple use case, so that I am able to understand the requirements? Thanks in advanca and all the best!