Fix smidge bundles not always invalidated between backoffice versions. (#11700)

* Introduced new smidge CacheBuster with sensible defaults.

* Bring back reset functionality in SmidgeRuntimeMinifier

* Clearer obsolete messaging.

src/Umbraco.Core/Configuration/IEntryAssemblyMetadata.cs

@@ -0,0 +1,18 @@
+namespace Umbraco.Cms.Core.Configuration
+{
+    /// <summary>
+    /// Provides metadata about the entry assembly.
+    /// </summary>
+    public interface IEntryAssemblyMetadata
+    {
+        /// <summary>
+        /// Gets the Name of entry assembly.
+        /// </summary>
+        public string Name { get; }
+
+        /// <summary>
+        /// Gets the InformationalVersion string for entry assembly.
+        /// </summary>
+        public string InformationalVersion { get; }
+    }
+}