include theme resources on server page load, add IUpgradeable interface to provide site-based versioning support

Oqtane.Server/Infrastructure/Interfaces/IInstallable.cs

@@ -1,5 +1,3 @@
-using Microsoft.EntityFrameworkCore;
-using Oqtane.Enums;
 using Oqtane.Models;
 
 namespace Oqtane.Infrastructure

Oqtane.Server/Infrastructure/Interfaces/IUpgradeable.cs

@@ -0,0 +1,11 @@
+using Oqtane.Models;
+
+namespace Oqtane.Infrastructure
+{
+    public interface IUpgradeable
+    {
+        string GetVersions(Alias alias);
+
+        bool Upgrade(Alias alias, string version);
+    }
+}