Remove unused usings

This addresses the new issues identified in SonarCloud analysis

Emby.Drawing/ImageProcessor.cs

@@ -8,7 +8,6 @@ using MediaBrowser.Common.Extensions;
 using MediaBrowser.Controller;
 using MediaBrowser.Controller.Drawing;
 using MediaBrowser.Controller.Entities;
-using MediaBrowser.Controller.Library;
 using MediaBrowser.Controller.MediaEncoding;
 using MediaBrowser.Model.Drawing;
 using MediaBrowser.Model.Entities;

MediaBrowser.Common/IApplicationHost.cs

@@ -2,8 +2,6 @@ using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using MediaBrowser.Common.Plugins;
-using MediaBrowser.Model.Updates;
-using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace MediaBrowser.Common

MediaBrowser.MediaEncoding/Encoder/MediaEncoder.cs

@@ -19,7 +19,6 @@ using MediaBrowser.Model.Globalization;
 using MediaBrowser.Model.IO;
 using MediaBrowser.Model.MediaInfo;
 using MediaBrowser.Model.System;
-using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging;
 using System.Diagnostics;