Implement `file_write' action

lib/producer/core/actions/file_writer.rb

@@ -0,0 +1,19 @@
+module Producer
+  module Core
+    module Actions
+      class FileWriter < Action
+        def apply
+          env.remote.fs.file_write path, content
+        end
+
+        def path
+          arguments[0]
+        end
+
+        def content
+          arguments[1]
+        end
+      end
+    end
+  end
+end