Adding cli namespace normalizer.

Reference: https://stackoverflow.com/questions/773557/which-characters-are-allowed-in-a-vs-project-name
Reference: dcf5adbd4b/src/Microsoft.TemplateEngine.Orchestrator.RunnableProjects/ValueForms/DefaultSafeNamespaceValueFormModel.cs (L35)

framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/Args/CommandLineArgumentParser.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Volo.Abp.Cli.Utils;
 using Volo.Abp.DependencyInjection;
 
 namespace Volo.Abp.Cli.Args
@@ -40,6 +41,7 @@ namespace Volo.Abp.Cli.Args
 
             if (!argumentList.Any())
             {
+                target = NamespaceHelper.NormalizeNamespace(target);
                 return new CommandLineArgs(command, target);
             }
 

framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/Utils/NamespaceHelper.cs

@@ -0,0 +1,21 @@
+using System.Text.RegularExpressions;
+using JetBrains.Annotations;
+
+namespace Volo.Abp.Cli.Utils
+{
+    public static class NamespaceHelper
+    {
+        public static string NormalizeNamespace([CanBeNull] string value)
+        {
+            if (string.IsNullOrEmpty(value))
+            {
+                return value;
+            }
+
+            value = Regex.Replace(value, @"(^\s+|\s+$)", "");
+            value = Regex.Replace(value, @"(((?<=\.)|^)((?=\d)|\.)|[^\w\.])|(\.$)", "_");
+
+            return value;
+        }
+    }
+}