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

feat(emailer): add Postmark and Resend providers

backend/Modules/Memberships/Data/MembershipState.cs

@@ -0,0 +1,8 @@
+namespace Hutopy.Modules.Memberships.Data;
+
+public enum MembershipState
+{
+    Pending,
+    Active,
+    Inactive
+}