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

feat(emailer): add Postmark and Resend providers

backend/Infrastructure/BlobStorage/Contracts/SubDirectoryNames.cs

@@ -0,0 +1,8 @@
+namespace Hutopy.Infrastructure.BlobStorage.Contracts;
+
+public static class SubDirectoryNames
+{
+    public const string Profile = "profile";
+    public const string Contents = "contents";
+    public const string Albums = "albums";
+}