Add buttons for hiding watched videos

Fix #448

Shared/Views/HideWatchedButtons.swift

@@ -0,0 +1,35 @@
+import Defaults
+import SwiftUI
+
+struct HideWatchedButtons: View {
+    @Default(.hideWatched) private var hideWatched
+
+    var body: some View {
+        Button {
+            hideWatched.toggle()
+        } label: {
+            Group {
+                if hideWatched {
+                    Label("Watched: hidden", systemImage: "clock")
+                        .help("Watched: hidden")
+                } else {
+                    Label("Watched: visible", systemImage: "clock.fill")
+                        .help("Watched: visible")
+                }
+            }
+            #if os(tvOS)
+            .font(.caption)
+            .imageScale(.small)
+            #endif
+        }
+        .transaction { t in t.disablesAnimations = true }
+    }
+}
+
+struct HideWatchedButtons_Previews: PreviewProvider {
+    static var previews: some View {
+        VStack {
+            HideWatchedButtons()
+        }
+    }
+}