Fixes #2486 - Removes old Border and fixes a litany of related things

[tig]

Fixes #2468

Also:

• Fixes Refactor TextFormatter tests #2521
• BREAKING CHANGE: Renames BorderStyle to LineStyle and moves defn to LineCanvas
• Refactors some of View
  • renames privates with_ etc...
  • Pulls HotKey code from Button
• BREAKING CHANGE: Removes many parameterized constructors from Dialog, Window, FrameView etc...
• Renames Toplevel.EnsureVisibleBounds to GetLocationThatFits to be more clear
• Adds, Refactors, cleans up, and renames many unit tests

Notes:

• The various Borders UI Catalog scenarios are still in a hacky condition

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