Merge branch 'main' into pr/99

* main:
  Wording
  Remove accessory images using tags rather than labels
  Update readme to point to ghcr.io/mrsked/mrsk
  Validate that all roles have hosts
  Commander needn't accumulate configuration
  Pull latest image tag, so we can identity it
  Default to deploying the config version
  Remove unneeded Dockerfile.dind, update Readme
  add D-in-D dockerfile, update Readme

test/commands/accessory_test.rb

@@ -137,7 +137,7 @@ class CommandsAccessoryTest < ActiveSupport::TestCase
 
   test "remove image" do
     assert_equal \
-      "docker image prune --all --force --filter label=service=app-mysql",
+      "docker image rm --force private.registry/mysql:8.0",
       @mysql.remove_image.join(" ")
   end
 end

test/commands/app_test.rb

@@ -188,12 +188,6 @@ class CommandsAppTest < ActiveSupport::TestCase
       new_command.current_running_version.join(" ")
   end
 
-  test "most_recent_version_from_available_images" do
-    assert_equal \
-      "docker image ls --format \"{{.Tag}}\" dhh/app | head -n 1",
-      new_command.most_recent_version_from_available_images.join(" ")
-  end
-
   test "list_containers" do
     assert_equal \
       "docker container ls --all --filter label=service=app --filter label=role=web",