Add inline comments about boot order

[pastudan]

I found the BOOT_ORDER docs hard to find, figured this might help some folks

[timg236]

This is duplication of the online and will get out of date and be incomplete . If you can see an appropriate place to add a link in the README.md files then that would be better.

[pastudan]

I updated the file to just link to the appropriate documentation so it won't get out of date

[timg236]

Thanks