Add DbModelOptions record for entity configuration

Introduced DbModelOptions in ReC.Infrastructure.Options to encapsulate collections of EntityOptions and VirtualEntityOptions, providing a structured way to configure entities and virtual entities. Both properties are initialized to empty collections by default.

src/ReC.Infrastructure/Options/DbModelOptions.cs

@@ -0,0 +1,10 @@
+using ReC.Infrastructure.Options.Shared;
+
+namespace ReC.Infrastructure.Options;
+
+public record DbModelOptions
+{
+    public IEnumerable<EntityOptions> Entities { get; init; } = [];
+
+    public IEnumerable<VirtualEntityOptions> VirtualEntities { get; init; } = [];
+}