Create user scenarios with regard to the scope of Tails

Similar to the PELD (https://tails.boum.org/contribute/design/), try to create user scenarios with regard to the scope of Tails as noted in tails_scope from the summit 2016.

We’d probably want to use Gherkin (https://github.com/cucumber/cucumber/wiki/Gherkin) for these scenarios.

Related issues

Related to #11777
Related to #9814
Related to #11162 (closed)
Related to #7627

Original created by @u on 11778 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information