V10 - Reduce usage of temp AspNetCoreHostingEnvironment (#12270)

* Move MapPathWebRoot & MapPathContentRoot to extension methods.

* Set AspNetCoreHostingEnvironment ApplicationId without service provider.

* Drop some usages of TempHostingEnvironment

* Logging setup cleanup - AppDomainId has no value (it is always "1")

Creating new AppDomains isn't possible in .Net core.
Attempting to do so results in a platform exception.

A dotnet core process has a single AppDomain instance whose Id property
is always the integer 1.

* Setup logging without IHostingEnvironment

* Mark IUmbracoBuilder.BuilderHostingEnvironment obsolete
And remove internal usages.

* Typeloader no longer uses umbraco-types.list

* Added UmbracoHost - setup serilog two-stage init.

* Add ApplicationIdEnricher

* Defensive tweaks for those not using UmbracoHost

* Drop UmbracoHost static class

* Setup runtime logger without host builder extensions.

* Prevent RefreshingRazorViewEngine related explosions

* Filescoped namespaces for new classes.

* Apply suggestions from code review

src/Umbraco.Web.Common/Extensions/ApplicationDiscriminatorExtensions.cs

@@ -0,0 +1,35 @@
+using System;
+using Microsoft.AspNetCore.DataProtection.Infrastructure;
+using Umbraco.Extensions;
+
+namespace Umbraco.Cms.Web.Common.Extensions
+{
+    /// <summary>
+    /// Contains extension methods for the <see cref="IApplicationDiscriminator" /> interface.
+    /// </summary>
+    public static class ApplicationDiscriminatorExtensions
+    {
+        private static string s_applicationId;
+
+        /// <summary>
+        /// Gets an application id which respects downstream customizations.
+        /// </summary>
+        /// <remarks>
+        /// Hashed to obscure any unintended infrastructure details e.g. the default value is ContentRootPath.
+        /// </remarks>
+        public static string GetApplicationId(this IApplicationDiscriminator applicationDiscriminator)
+        {
+            if (s_applicationId != null)
+            {
+                return s_applicationId;
+            }
+
+            if (applicationDiscriminator == null)
+            {
+                throw new ArgumentNullException(nameof(applicationDiscriminator));
+            }
+
+            return s_applicationId = applicationDiscriminator.Discriminator.GenerateHash();
+        }
+    }
+}