Added retreival of agenst, started basic flow

FarmmapsHaulmkilling/HaulmkillingService.cs

@@ -1,7 +1,36 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using FarmmapsApi.Services;
+using FarmmapsHaulmkilling.Models;
+using Microsoft.Extensions.Logging;
+
 namespace FarmmapsHaulmkilling
 {
     public class HaulmkillingService
     {
+        private readonly ILogger<HaulmkillingService> _logger;
+        private readonly FarmmapsApiService _farmmapsApiService;
+        private readonly GeneralService _generalService;
+
+        public HaulmkillingService(ILogger<HaulmkillingService> logger, FarmmapsApiService farmmapsApiService,
+            GeneralService generalService)
+        {
+            _logger = logger;
+            _farmmapsApiService = farmmapsApiService;
+            _generalService = generalService;
+        }
         
+        public async Task<List<HaulmkillingAgent>> GetHaulmkillingAgents()
+        {
+            var itemType = "vnd.farmmaps.package.vra.haulmkilling";
+            var vraHerbicideDataItems = await _farmmapsApiService.GetItemsAsync(string.Empty, itemType);
+
+            var item = vraHerbicideDataItems.FirstOrDefault();
+            if (item == null)
+                return null;
+
+            return item.Data.ContainsKey("agents") ? item.Data["agents"].ToObject<List<HaulmkillingAgent>>() : null;
+        }
     }
 }