Add Transaction Merchant management (#686)

* Add basid crud for merchant management

* Tweak UI and add localization

* Fix lint

* Add filtering by merchant

* Add tests

* Add stimulus controller to update avatar in merchant form

* Add line between merchant rows

* Change default merchant color

* Cleanup

test/models/family_test.rb

@@ -51,6 +51,12 @@ class FamilyTest < ActiveSupport::TestCase
     end
   end
 
+  test "should destroy dependent merchants" do
+    assert_difference("Transaction::Merchant.count", -@family.transaction_merchants.count) do
+      @family.destroy
+    end
+  end
+
   test "should calculate total assets" do
     expected = @expected_snapshots.last["assets"].to_d
     assert_equal Money.new(expected), @family.assets