[Task] Create Full disk Installation under Installation Guide

[Eric Turgeon]

• Create documentation/source/user/installation-guide/full-disk-installation.md
• Create the documentation to install GhostBSD on a disk similar to https://wiki.ghostbsd.org/index.php/Installation_Guide#Starting_GhostBSD_Live_Media and bellow.
• Add Full disk Installation file in documentation/source/user/installation-guide/installation-guide.md to list it in the side menu
  Note: The wiki is outdated, please no word for word and take new pictures.