Fixes #2537, #3691, #3406 - New Overlapped Design, mouse/keyboard sizing - Progress on #2491

[tig]

Fixes

• Partially Addresses Get rid of Toplevel - Introduce Runnable and Overlapped instead #2491 by
  • Finishes ViewArrangement.Overlapped support
  • Fixes Add mouse/keyboard resizing of views #2537
  • Fixes Slider: API for setting options is clunky #3735
  • Fixes Fix focus and keyboard nav with Adornments #3406
  • Fixes Move all rendering out of Toplevel, FrameView, Window, etc... into View. #2484

Proposed Changes/Todos

• Remove temporary code in OnDrawContent and get z-order correct.
• Enhance Bars scenario to illustrate Popover menu concept
• Enhance Navigation scenario with ArrangementEditor; like AdornmentEditor makes it wasy to change view settings related to arrangement for testing/demos.
• Clone Navigation scenario to Arrangement scenario - one for each
• Implement support for ViewArrangement.Resizable
• Fix Draw
• Remove more code from Toplevel - See how far I can get in removing Toplevel allogether without re-doing all the Runnable stuff (for a later PR focused on IRunnable).
• Fix Add mouse/keyboard resizing of views #2537
• Update docfx/docs and other API docs

For future PRs

• Enable Runnable concept
• Fix Tiled mode: need a way to declare tiled view size dependencies #3741
• Fix Navigation Scenario: Add a TabStop Editor  #3742
• Fix Popover - A consistent way of enabling a Subview to popup outside of a View #3691
• This PR re-broke the cursor flickering issue (Long-standing repaint-flicker issue. #3408). Will fix this in Re-factor Cursor handling per ./docfx/docs/cursor.md #3444
• Create a scenario that illustrates an "MDI" like app (replacing BackgroundWorkerCollection). Show how MenuBar and StatusBar can be in any View, even multiple.
• Fix Subviews in Adornments that are not ViewArrangement.Fixed are not supported #3743
• Fix Remove need for TileView - Use LineCanvas to draw borders and auto-join borders #2483

Pull Request checklist:

• I've named my PR in the form of "Fixes #issue. Terse description."
• My code follows the style guidelines of Terminal.Gui - if you use Visual Studio, hit CTRL-K-D to automatically reformat your files before committing.
• My code follows the Terminal.Gui library design guidelines
• I ran dotnet test before commit
• I have made corresponding changes to the API documentation (using /// style comments)
• My changes generate no new warnings
• I have checked my code and corrected any poor grammar or misspellings
• I conducted basic QA to assure all features are working

[tig]

Closing. This branch is now rebased with

• Fixes #3570 & #3561. Fixes a bunch of EventArgs sins #3571