- Created new service: IStayExportService" for common export operations.
- Updated older services to be "IStayExportFormatProvider". This services will only implement the export format.
- Renamed "IStayExportServiceFactory" to "IStayExportFormatProviderFactory" as this factory now is used to get the format providers for the given format.
- 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.