Plugin prerequisites - Added UI for installing/removing prerequisites

Plugin settings - Added button to reload plugin from disk
Confirm dialogs - Made cancel text optional so you can hide the button

src/Artemis.Core/Plugins/Prerequisites/PrerequisiteAction/DeleteFileAction.cs

@@ -0,0 +1,44 @@
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Artemis.Core
+{
+    /// <summary>
+    ///     Represents a plugin prerequisite action that deletes a file
+    /// </summary>
+    public class DeleteFileAction : PluginPrerequisiteAction
+    {
+        /// <summary>
+        ///     Creates a new instance of a copy folder action
+        /// </summary>
+        /// <param name="name">The name of the action</param>
+        /// <param name="target">The target folder to delete recursively</param>
+        public DeleteFileAction(string name, string target) : base(name)
+        {
+            Target = target;
+            ProgressIndeterminate = true;
+        }
+
+        /// <summary>
+        ///     Gets or sets the target directory
+        /// </summary>
+        public string Target { get; }
+
+        /// <inheritdoc />
+        public override async Task Execute(CancellationToken cancellationToken)
+        {
+            ShowProgressBar = true;
+            Status = $"Removing {Target}";
+
+            await Task.Run(() =>
+            {
+                if (File.Exists(Target))
+                    File.Delete(Target);
+            }, cancellationToken);
+
+            ShowProgressBar = false;
+            Status = $"Removed {Target}";
+        }
+    }
+}