Initial commit for tooltip

Tooltip was made as it assumed to be. As it was expected, tooltip covers Scrollbar and user can not use the scroll with mouse until tooltip is opened. Please review code and close that pull request  https://github.com/DynamoDS/Dynamo/pull/2026 because it was made in the wrong brach. I apologize about that wrong pull request, that will not happen again.
I believe ```SearchView.xaml.cs``` being in ```Views``` has the advantage of being able to access to ```DynamoView```, could you get help from @vmoyseenko and see how other parts of the view codes are accessing ```DynamoView```? Because it has the window and its height.