Added suuport to inject an IOqtaneDatabase in EntityBuilders to allow each Database to control certain Migration behaviors. Also updated Installer to dynamically build Database Configuration section

Oqtane.Server/Migrations/Framework/MultiDatabaseMigrationsAssembly.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Migrations.Internal;
+using Oqtane.Interfaces;
+using Oqtane.Repository.Databases.Interfaces;
+
+namespace Oqtane.Migrations.Framework
+{
+    public class MultiDatabaseMigrationsAssembly: MigrationsAssembly
+    {
+        private readonly IEnumerable<IOqtaneDatabase> _databases;
+
+        public MultiDatabaseMigrationsAssembly(
+            ICurrentDbContext currentContext,
+            IDbContextOptions options,
+            IMigrationsIdGenerator idGenerator,
+            IDiagnosticsLogger<DbLoggerCategory.Migrations> logger)
+            : base(currentContext, options, idGenerator, logger)
+        {
+            var multiDatabaseContext = currentContext.Context as IMultiDatabase;
+            if (multiDatabaseContext != null) _databases = multiDatabaseContext.Databases;
+        }
+        public override Migration CreateMigration(TypeInfo migrationClass, string activeProvider)
+        {
+            var hasCtorWithCacheOptions = migrationClass.GetConstructor(new[] { typeof(IEnumerable<IOqtaneDatabase>) }) != null;
+
+            if (hasCtorWithCacheOptions)
+            {
+                var migration = (Migration)Activator.CreateInstance(migrationClass.AsType(), _databases);
+                if (migration != null)
+                {
+                    migration.ActiveProvider = activeProvider;
+                    return migration;
+                }
+            }
+
+            return base.CreateMigration(migrationClass, activeProvider);
+        }
+    }
+}