TUN-3201: Create base cloudflared UI structure

vendor/github.com/rivo/tview/borders.go

@@ -0,0 +1,45 @@
+package tview
+
+// Borders defines various borders used when primitives are drawn.
+// These may be changed to accommodate a different look and feel.
+var Borders = struct {
+	Horizontal  rune
+	Vertical    rune
+	TopLeft     rune
+	TopRight    rune
+	BottomLeft  rune
+	BottomRight rune
+
+	LeftT   rune
+	RightT  rune
+	TopT    rune
+	BottomT rune
+	Cross   rune
+
+	HorizontalFocus  rune
+	VerticalFocus    rune
+	TopLeftFocus     rune
+	TopRightFocus    rune
+	BottomLeftFocus  rune
+	BottomRightFocus rune
+}{
+	Horizontal:  BoxDrawingsLightHorizontal,
+	Vertical:    BoxDrawingsLightVertical,
+	TopLeft:     BoxDrawingsLightDownAndRight,
+	TopRight:    BoxDrawingsLightDownAndLeft,
+	BottomLeft:  BoxDrawingsLightUpAndRight,
+	BottomRight: BoxDrawingsLightUpAndLeft,
+
+	LeftT:   BoxDrawingsLightVerticalAndRight,
+	RightT:  BoxDrawingsLightVerticalAndLeft,
+	TopT:    BoxDrawingsLightDownAndHorizontal,
+	BottomT: BoxDrawingsLightUpAndHorizontal,
+	Cross:   BoxDrawingsLightVerticalAndHorizontal,
+
+	HorizontalFocus:  BoxDrawingsDoubleHorizontal,
+	VerticalFocus:    BoxDrawingsDoubleVertical,
+	TopLeftFocus:     BoxDrawingsDoubleDownAndRight,
+	TopRightFocus:    BoxDrawingsDoubleDownAndLeft,
+	BottomLeftFocus:  BoxDrawingsDoubleUpAndRight,
+	BottomRightFocus: BoxDrawingsDoubleUpAndLeft,
+}