feat(templates): add service language template management

Add normalized service and template catalogs, scoped administration, migration, validation, and regression coverage.

Ref: IT-1601

HrynCo.NotificationService.Services.Tests/DevelopmentDataSeederTests.cs

@@ -11,6 +11,7 @@ public sealed class DevelopmentDataSeederTests
 {
     private readonly IEmailChannelRepository _channels = Substitute.For<IEmailChannelRepository>();
     private readonly IEmailTemplateRepository _templates = Substitute.For<IEmailTemplateRepository>();
+    private readonly INotificationServiceRepository _services = Substitute.For<INotificationServiceRepository>();
 
     [Fact]
     public async Task SeedAsync_WhenConfigurationIsMissing_CreatesMailpitChannelAndTestTemplate()
@@ -69,6 +70,7 @@ public sealed class DevelopmentDataSeederTests
     private DevelopmentDataSeeder CreateSeeder() => new(
         _channels,
         _templates,
+        _services,
         NullLogger<DevelopmentDataSeeder>.Instance);
 
     private static bool IsMailpitChannel(EmailChannel channel)