Refactored `MessagingServiceApplicationConfiguration` to simplify the tracking of the LuckyPennySoft license key configuration by replacing the `_configured` tuple with a boolean. Removed email account configuration methods from this class.
Updated `MessagingServiceInfrastructureConfiguration` to introduce a new `_configured` tuple for tracking `RabbitMqConnectionFactory` and `EmailAccounts` configurations. Added methods for configuring email accounts and updated the `EnsureRabbitMqConnectionFactoryAdded` method to include email account checks.
Changed the namespace of `EmailAccountsOptions.cs` to `DigitalData.MessagingService.Infrastructure.Options`.
Modified `Program.cs` to include email account configuration in the infrastructure setup.
Added new files `DependencyInjectionExtensions.cs` and `MessagingServiceConfiguration.cs` as placeholders for future extensions, wrapped in `#if NET` directives.
Removed an `<ItemGroup>` from `DigitalData.MessagingService.Infrastructure.csproj` and updated `DigitalData.MessagingService.Client.csproj` for XML compliance.