Always send the clear env to the container

Secret and clear env variables have different lifecycles. The clear ones
are part of the repo, so it makes sense to always deploy them with the
rest of the repo.

The secret ones are external so we can't be sure that they are up to
date, therefore they require an explicit push via `envify` or `env push`.

We'll keep the env file, but now it just contains secrets. The clear
values are passed directly to `docker run`.

lib/kamal/configuration/accessory.rb

@@ -42,23 +42,13 @@ class Kamal::Configuration::Accessory
   end
 
   def env
-    specifics["env"] || {}
-  end
-
-  def env_file
-    Kamal::EnvFile.new(env)
-  end
-
-  def host_env_directory
-    File.join config.host_env_directory, "accessories"
-  end
-
-  def host_env_file_path
-    File.join host_env_directory, "#{service_name}.env"
+    Kamal::Configuration::Env.from_config \
+      config: specifics.fetch("env", {}),
+      secrets_file: File.join(config.host_env_directory, "accessories", "#{service_name}.env")
   end
 
   def env_args
-    argumentize "--env-file", host_env_file_path
+    env.args
   end
 
   def files
@@ -111,10 +101,10 @@ class Kamal::Configuration::Accessory
     end
 
     def with_clear_env_loaded
-      (env["clear"] || env).each { |k, v| ENV[k] = v }
+      env.clear.each { |k, v| ENV[k] = v }
       yield
     ensure
-      (env["clear"] || env).each { |k, v| ENV.delete(k) }
+      env.clear.each { |k, v| ENV.delete(k) }
     end
 
     def read_dynamic_file(local_file)