Added GRUB docs, Added netboot.xyz

boot/grub/persistent/docs/20_outline

@@ -0,0 +1,33 @@
+20 Outline
+**********
+
+Some platforms have features which allows to implement some commands
+useless or not implementable on others.
+
+   Quick summary:
+
+   Information retrieval:
+
+   * mipsel-loongson: lsspd
+   * mips-arc: lsdev
+   * efi: lsefisystab, lssal, lsefimmap, lsefi
+   * i386-pc: lsapm
+   * i386-coreboot: lscoreboot, coreboot_boottime, cbmemc
+   * acpi-enabled (i386-pc, i386-coreboot, i386-multiboot, *-efi):
+     lsacpi
+
+   Workarounds for platform-specific issues:
+   * i386-efi/x86_64-efi: loadbios, fakebios, fix_video
+   * acpi-enabled (i386-pc, i386-coreboot, i386-multiboot, *-efi): acpi
+     (override ACPI tables)
+   * i386-pc: drivemap
+   * i386-pc: sendkey
+
+   Advanced operations for power users:
+   * x86: iorw (direct access to I/O ports)
+
+   Miscelaneous:
+   * cmos (x86-*, ieee1275, mips-qemu_mips, mips-loongson): cmostest
+     (used on some laptops to check for special power-on key), cmosclean
+   * i386-pc: play
+