This PR adds minor adjustments to sign up procedures in prerequisite
sections.
* Adding one word `verified` to instances of `Docker account` in
prerequisite sections is a subtle, unobtrusive change that returning,
verified users can gloss over, while still prompting new users to verify
their email if they haven't yet.
* Changes stick to specific instances in `## Prerequisite` sections and
does not add `verified` to every instance (which would be obtrusive).
* Edits to Create Account doc to remove redundant callouts, consolidate
steps for shorter procedures, and add context about verification.
* If an instance of `Docker account` links to /create-account and not
the sign up page, I did not add `verification`.
* **Note**: we may want to consider a direct link to a sign up page
rather than linking them to a create account page. This can be a
separate PR, however.
## Description
In this PR I added an article that was missing from several similar
pages.
## Reviews
- [ ] Technical review
- [x] Editorial review
- [ ] Product review
