Initial functionality of player items queue

Fix environment objects

Hide video player placeholder on tvOS

Queue improvements

Extensions/View+Borders.swift

@@ -0,0 +1,16 @@
+import Foundation
+import SwiftUI
+
+extension View {
+    func borderTop(height: Double, color: Color = Color(white: 0.7, opacity: 1)) -> some View {
+        verticalEdgeBorder(.top, height: height, color: color)
+    }
+
+    func borderBottom(height: Double, color: Color = Color(white: 0.7, opacity: 1)) -> some View {
+        verticalEdgeBorder(.bottom, height: height, color: color)
+    }
+
+    private func verticalEdgeBorder(_ edge: Alignment, height: Double, color: Color) -> some View {
+        overlay(Rectangle().frame(width: nil, height: height, alignment: .top).foregroundColor(color), alignment: edge)
+    }
+}