many fixes and improvements - rework for modules/ and common/

feat(emailer): add Postmark and Resend providers

backend/Modules/Contents/DependencyInjection.cs

@@ -0,0 +1,27 @@
+using Hutopy.Modules.Contents.Data;
+
+namespace Hutopy.Modules.Contents;
+
+public static class DependencyInjection
+{
+    public static WebApplicationBuilder AddContentModule(
+        this WebApplicationBuilder builder,
+        Action<DbContextOptionsBuilder>? configureAction = null)
+    {
+        builder.Services.AddDbContext<ContentsDbContext>(configureAction);
+
+        return builder;
+    }
+
+    public static async Task<IApplicationBuilder> UseContentModuleAsync(
+        this IApplicationBuilder app,
+        CancellationToken cancellationToken = default)
+    {
+        var scopeFactory = app.ApplicationServices.GetRequiredService<IServiceScopeFactory>();
+        using var scope = scopeFactory.CreateScope();
+        await using var context = scope.ServiceProvider.GetRequiredService<ContentsDbContext>();
+        await context.Database.MigrateAsync(cancellationToken);
+
+        return app;
+    }
+}