refactor buyer and insured and add more policy types

lib/policy_service/aggregates/fire_contents_policy_application.ex

@@ -0,0 +1,22 @@
+defmodule PolicyService.Aggregates.FireContentsPolicyApplication do
+  use PolicyService.Aggregates.PolicyApplication,
+    policy_type: "fire_contents",
+    commands: PolicyService.Commands.FireContentsPolicy
+
+  def validate_details(%{
+        "location" => location,
+        "contents_value" => value,
+        "property_use" => use_type,
+        "security_measures" => measures,
+        "high_value_items" => items
+      })
+      when is_binary(location) and byte_size(location) > 0 and
+             is_number(value) and value > 0 and
+             is_binary(use_type) and byte_size(use_type) > 0 and
+             is_list(measures) and
+             is_list(items) do
+    :ok
+  end
+
+  def validate_details(_), do: {:error, :invalid_fire_contents_details}
+end