add base class for bootloaders and none bootloader

src/lib/bootloader/bootloader_base.rb

@@ -0,0 +1,18 @@
+require "bootloader/sysconfig"
+
+module Bootloader
+  class BootloaderBase
+    def write
+      write_sysconfig
+    end
+
+    def read
+    end
+
+  protected
+    def write_sysconfig
+      sysconfig = Bootloader::Sysconfig.new(bootloader: name)
+      sysconfig.write
+    end
+  end
+end

src/lib/bootloader/none_bootloader.rb

@@ -0,0 +1,19 @@
+require "yast"
+
+Yast.import "HTML"
+
+module Bootloader
+  # Represents when bootloader want user manage itself
+  class NoneBootloader < BootloaderBase
+    def summary
+      [Yast::HTML.Colorize(
+        _("Do not install any boot loader"),
+        "red"
+      )]
+    end
+
+    def name
+      "none"
+    end
+  end
+end