Update info.description

[eric-murray]

Purpose:

• documentation

What this PR does / why we need it:

Updates info.description with:

• New Commonalities template for User identification
• Add section on multi-SIM scenario handling

Which issue(s) this PR fixes:

Fixes #None
But helps with #212 and #222

Special notes for reviewers:

Will need to revisit once multi-SIM scenario handling is standardised

Changelog input

 release-note
 - Update info.description section for user identification and multi-SIM scenario handling

Additional documentation

None

[bigludo7]

Look good for me. Indeed the multi-SIM could be updated later.

[eric-murray]

I updated all YAMLs with text on multi-SIM scenario handling, and also the "identifying the device from the token" text for the device roaming API.

I had a question on identifying the device for the subscription APIs. Currently device is a required parameter of the Subscription Request. So does this mean that subscriptions can only be created with a 2-legged token? Or should device actually be optional?