Added playlists view. Added messaging service. Added logic for adding and deleting playlists.

Harmonia.WinUI/Views/PlaylistsView.xaml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="utf-8"?>
+<UserControl
+    x:Class="Harmonia.WinUI.Views.PlaylistsView"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Harmonia.WinUI.Views"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:vm="using:Harmonia.WinUI.ViewModels"
+    xmlns:playlists="using:Harmonia.Core.Playlists"
+    DataContext="{Binding Source={StaticResource Locator}, Path=PlaylistsViewModel}"
+    d:DataContext="{d:DesignInstance Type=vm:PlaylistsViewModel, IsDesignTimeCreatable=True}"
+    mc:Ignorable="d">
+    <UserControl.Resources>
+        <DataTemplate x:Key="PlaylistTemplate" x:DataType="playlists:Playlist">
+            <StackPanel Orientation="Horizontal" Spacing="8" VerticalAlignment="Bottom">
+                <Viewbox Height="24" Width="24">
+                    <PathIcon Data="{StaticResource MusicNoteList}" />
+                </Viewbox>
+                <TextBlock Text="{x:Bind Name}" FontSize="16" VerticalAlignment="Center" />
+            </StackPanel>
+        </DataTemplate>
+    </UserControl.Resources>
+    <Grid Margin="10">
+        <ListView
+            ItemsSource="{Binding Playlists, Mode=OneWay}"
+            SelectedItem="{Binding SelectedPlaylist, Mode=TwoWay}"
+            ItemTemplate="{StaticResource PlaylistTemplate}">
+        </ListView>
+    </Grid>
+</UserControl>