Split NugetHelper code into separate classes

src/GlobalShared.DotSettings

@@ -228,6 +228,8 @@
     <s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ECSharpPlaceEmbeddedOnSameLineMigration/@EntryIndexedValue">True</s:Boolean>
     <s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ECSharpUseContinuousIndentInsideBracesMigration/@EntryIndexedValue">True</s:Boolean>
     <s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EMigrateBlankLinesAroundFieldToBlankLinesAroundProperty/@EntryIndexedValue">True</s:Boolean>
+    <s:Boolean x:Key="/Default/UserDictionary/Words/=discoverability/@EntryIndexedValue">True</s:Boolean>
     <s:Boolean x:Key="/Default/UserDictionary/Words/=Nupkg/@EntryIndexedValue">True</s:Boolean>
+    <s:Boolean x:Key="/Default/UserDictionary/Words/=nuspec/@EntryIndexedValue">True</s:Boolean>
     <s:Boolean x:Key="/Default/UserDictionary/Words/=prerelease/@EntryIndexedValue">True</s:Boolean>
 </wpf:ResourceDictionary>

src/NuGetForUnity.Cli/Fakes/UnityPreImportedLibraryResolver.cs

@@ -1,7 +1,5 @@
 #nullable enable
 
-using System.Collections.Generic;
-
 namespace NugetForUnity
 {
     /// <summary>
@@ -10,13 +8,15 @@ namespace NugetForUnity
     internal static class UnityPreImportedLibraryResolver
     {
         /// <summary>
-        ///     Gets all libraries that are already imported by unity so we shouldn't / don't need to install them as NuGet packages.
+        ///     Check if a package is already imported in the Unity project e.g. is a part of Unity.
         /// </summary>
-        /// <returns>A set of all names of libraries that are already imported by unity.</returns>
-        internal static HashSet<string> GetAlreadyImportedLibs()
+        /// <param name="package">The package of witch the identifier is checked.</param>
+        /// <param name="log">Whether to log a message with the result of the check.</param>
+        /// <returns>If it is included in Unity.</returns>
+        public static bool IsAlreadyImportedInEngine(INugetPackageIdentifier package, bool log = true)
         {
             // the CLI is running outside of Unity so we can't easily detect what libraries are imported by the Unity Engine.
-            return new HashSet<string>();
+            return false;
         }
     }
 }

src/NuGetForUnity.Cli/NuGetForUnity.Cli.sln.DotSettings

@@ -0,0 +1,6 @@
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+    <s:String x:Key="/Default/Environment/InjectedLayers/FileInjectedLayer/=1D5FC5A9A430BE4E8B4B103E47C6F342/RelativePath/@EntryValue">..\..\GlobalShared.DotSettings</s:String>
+    <s:Boolean x:Key="/Default/Environment/InjectedLayers/FileInjectedLayer/=1D5FC5A9A430BE4E8B4B103E47C6F342/@KeyIndexDefined">True</s:Boolean>
+    <s:Boolean x:Key="/Default/Environment/InjectedLayers/InjectedLayerCustomization/=File1D5FC5A9A430BE4E8B4B103E47C6F342/@KeyIndexDefined">True</s:Boolean>
+    <s:Double x:Key="/Default/Environment/InjectedLayers/InjectedLayerCustomization/=File1D5FC5A9A430BE4E8B4B103E47C6F342/RelativePriority/@EntryValue">1</s:Double>
+</wpf:ResourceDictionary>

src/NuGetForUnity.Cli/Program.cs

@@ -10,12 +10,20 @@
 
 namespace NuGetForUnity.Cli
 {
+    /// <summary>
+    ///     Simple command line interface to restore NuGet packages for Unity projects.
+    /// </summary>
     public static class Program
     {
         private static readonly string[] HelpOptions = { "-?", "-h", "--help" };
 
         private static string DefaultProjectPath => Directory.GetCurrentDirectory();
 
+        /// <summary>
+        ///     Starting point of the application.
+        /// </summary>
+        /// <param name="args">The command line arguments.</param>
+        /// <returns>The application exit code.</returns>
         public static int Main(string[] args)
         {
             var availableArguments = args.ToList();
@@ -52,7 +60,7 @@ public static int Main(string[] args)
             Application.SetUnityProjectPath(projectPath);
 
             // need to disable dependency installation as UnityPreImportedLibraryResolver.GetAlreadyImportedLibs is not working outside Unity.
-            NugetHelper.Restore(false);
+            NugetPackageRestorer.Restore(false);
             FixRoslynAnalyzerImportSettings();
             return Debug.HasError ? 1 : 0;
         }
@@ -72,13 +80,13 @@ private static void FixRoslynAnalyzerImportSettings()
                 return;
             }
 
-            if (NugetHelper.NugetConfigFile == null || !Directory.Exists(NugetHelper.NugetConfigFile.RepositoryPath))
+            if (!Directory.Exists(ConfigurationManager.NugetConfigFile.RepositoryPath))
             {
                 return;
             }
 
             UTF8Encoding? utf8NoBom = null;
-            foreach (var packageDirectoryPath in Directory.EnumerateDirectories(NugetHelper.NugetConfigFile.RepositoryPath))
+            foreach (var packageDirectoryPath in Directory.EnumerateDirectories(ConfigurationManager.NugetConfigFile.RepositoryPath))
             {
                 var analyzersDirectoryPath = Path.Combine(packageDirectoryPath, "analyzers");
                 if (!Directory.Exists(analyzersDirectoryPath))