Consider fine-tuning the pattern descriptions and diagrams

[danielfett]

I found a couple of issues with the current pattern descriptions and the diagrams — see the numbered steps in the diagrams below for details:

• In User-Transferred Session Data Pattern, the step C should be split into multiple steps: sending the qr code to the ID, displaying it to the user, and then the user scanning it
• In Backchannel-Transferred Session Pattern, the step C should be split up into two (request/response)
• In User-Transferred Authorization Data Pattern, step D is really two steps
• In User-Transferred Authorization Data Pattern, step E requires sending data back to AS, so becomes two steps

UTSDP

BTSP

UTADP