Extract Cord, Assets, and Execution concerns from App

It was getting crowded!

lib/kamal/commands/app/execution.rb

@@ -0,0 +1,27 @@
+module Kamal::Commands::App::Execution
+  def execute_in_existing_container(*command, interactive: false)
+    docker :exec,
+      ("-it" if interactive),
+      container_name,
+      *command
+  end
+
+  def execute_in_new_container(*command, interactive: false)
+    docker :run,
+      ("-it" if interactive),
+      "--rm",
+      *role_config&.env_args,
+      *config.volume_args,
+      *role_config&.option_args,
+      config.absolute_image,
+      *command
+  end
+
+  def execute_in_existing_container_over_ssh(*command, host:)
+    run_over_ssh execute_in_existing_container(*command, interactive: true), host: host
+  end
+
+  def execute_in_new_container_over_ssh(*command, host:)
+    run_over_ssh execute_in_new_container(*command, interactive: true), host: host
+  end
+end