Add campaign manager

Hcs.WebApp/BackgroundServices/CampaignManagers/ManagerBase.cs

@@ -0,0 +1,13 @@
+using Hcs.WebApp.Data.Hcs;
+
+namespace Hcs.WebApp.BackgroundServices.CampaignManagers
+{
+    public abstract class ManagerBase(OperationExecutionState state, IServiceScopeFactory scopeFactory, Campaign campaign) : IManager
+    {
+        protected readonly OperationExecutionState state = state;
+        protected readonly IServiceScopeFactory scopeFactory = scopeFactory;
+        protected readonly Campaign campaign = campaign;
+
+        public abstract Task StartAsync(CancellationToken cancellationToken);
+    }
+}