feat StayExport - Initial Implementation

- Created models for DB and DTOs: StayExportFile
- Added required db migrations.
- Added StayExportService and StayExportServiceFactory for stay exporting services.
- Added configuration options required for StayExport.

src/Somnia.GuestLog/Infrastructure/EntityConfigs/StayExportFileEntityConfig.cs

@@ -0,0 +1,33 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using Somnia.GuestLog.Models.Entities;
+
+namespace Somnia.GuestLog.Infrastructure.EntityConfigs;
+
+public class StayExportFileEntityConfig : IEntityTypeConfiguration<StayExportFile>
+{
+    public void Configure(EntityTypeBuilder<StayExportFile> builder)
+    {
+        builder.ToTable("StayExportFile");
+
+        //PK
+        builder.HasKey(e => e.Id);
+
+        builder.Property(e => e.Id)
+            .IsRequired()
+            .UseIdentityByDefaultColumn();
+
+        builder.ComplexProperty(e => e.ExportParams, e =>
+        {
+            e.ToJson();
+        });
+
+        builder.Property(e => e.ExportedPath)
+            .HasMaxLength(256);
+
+
+        builder.Property(e => e.ExportTime)
+            .IsRequired()
+            .HasColumnType(DbConsts.DbType_Timestamptz);
+    }
+}