SysD 5.0 review discussion - Authentication

[rbocsi]

The Arrowhead community is admonished to read and review the System Description (SysD) of Authentication v5.0 draft, available here:

• For easier reading, use the .pdf format.
• To reference exact lines use the .tex format.

Please read the document and share your comments and suggestions within this issue.

Originally posted by @borditamas in #88