v6.6 final GE

The last full release covering Grid Engine (GE) examples.

• Added OpenISS job examples
  • OpenISS YOLOv3 (@tariqghd)
  • OpenISS REID (@carlos-encs)
• Singularity section added (@smokhov)
• More FAQ updates (@yulgroper)
• More sister facilities (@smokhov)
• Add more published related work (@smokhov)
• General editing/proofreading (@yulgroper, @smokhov)