feat: implement ofac file service

src/SanctionsSearch.Worker/appsettings.Example.json

@@ -4,5 +4,16 @@
       "Default": "Information",
       "Microsoft.Hosting.Lifetime": "Information"
     }
+  },
+  "OfacFileServiceOptions": {
+    "Url": "https://sanctionslistservice.ofac.treas.gov/api/PublicationPreview/exports",
+    "SdnFileName": "SDN.CSV",
+    "AddressFileName": "ADD.CSV",
+    "AltNamesFileName": "ALT.CSV",
+    "CommentsFileName": "SDN_COMMENTS.CSV",
+    "ConPrimaryNameFileName": "CONS_PRIM.CSV",
+    "ConAddressesFileName": "CONS_ADD.CSV",
+    "ConAltNamesFileName": "CONS_ALT.CSV",
+    "ConCommentsFileName": "CONS_COMMENTS.CSV"
   }
-}
+}