Prerequisites - Finalized UI logic surrounding install/remove

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

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+using System;
+using System.IO;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using Humanizer;
+
+namespace Artemis.Core
+{
+    /// <summary>
+    ///     Represents a plugin prerequisite action that downloads a file
+    /// </summary>
+    public class DownloadFileAction : PluginPrerequisiteAction
+    {
+        /// <summary>
+        ///     Creates a new instance of a copy folder action
+        /// </summary>
+        /// <param name="name">The name of the action</param>
+        /// <param name="source">The source URL to download</param>
+        /// <param name="target">The target file to save as (will be created if needed)</param>
+        public DownloadFileAction(string name, string source, string target) : base(name)
+        {
+            Source = source ?? throw new ArgumentNullException(nameof(source));
+            Target = target ?? throw new ArgumentNullException(nameof(target));
+
+            ShowProgressBar = true;
+        }
+
+        /// <summary>
+        ///     Gets the source URL to download
+        /// </summary>
+        public string Source { get; }
+
+        /// <summary>
+        ///     Gets the target file to save as (will be created if needed)
+        /// </summary>
+        public string Target { get; }
+
+        /// <inheritdoc />
+        public override async Task Execute(CancellationToken cancellationToken)
+        {
+            using HttpClient client = new();
+            await using FileStream destinationStream = File.Create(Target);
+
+            void ProgressOnProgressReported(object? sender, EventArgs e)
+            {
+                if (Progress.ProgressPerSecond != 0)
+                    Status = $"Downloading {Target} - {Progress.ProgressPerSecond.Bytes().Humanize("#.##")}/sec";
+                else
+                    Status = $"Downloading {Target}";
+            }
+
+            Progress.ProgressReported += ProgressOnProgressReported;
+
+            // Get the http headers first to examine the content length
+            using HttpResponseMessage response = await client.GetAsync(Target, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
+            await using Stream download = await response.Content.ReadAsStreamAsync(cancellationToken);
+            long? contentLength = response.Content.Headers.ContentLength;
+
+            // Ignore progress reporting when no progress reporter was 
+            // passed or when the content length is unknown
+            if (!contentLength.HasValue)
+            {
+                ProgressIndeterminate = true;
+                await download.CopyToAsync(destinationStream, Progress, cancellationToken);
+            }
+            else
+            {
+                ProgressIndeterminate = false;
+                await download.CopyToAsync(contentLength.Value, destinationStream, Progress, cancellationToken);
+            }
+
+            Progress.ProgressReported -= ProgressOnProgressReported;
+
+            Progress.Report((1, 1));
+            Status = "Finished downloading";
+        }
+    }
+}