Create _child_student_create_account

[KatherineCox]

Here's a draft of instructions for students to sign up for an account and send their username to their instructor. I thought it would be nice to have something that could be dropped in to GDSCN books. Feedback welcome! I took bits from several of the existing books.

I went with making the steps H3s, because that seems to be the most common in existing books, usually looking something like:

• H1 Student Activity Guide
  • H2 Account Setup
    • H3 the steps of this child

(I have temporarily set the parent Rmd to point to this branch, so that the child will show up in the preview for this PR (chapter 8); I'll switch it before merging to main)

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The check: broken urls is currently being re-run :runner: Comment updated at 2022-10-25 with changes from be4ebfdcd1ea18e52d1704502fb9a3b0c2292dc3

[github-actions[bot]]

The check: spelling errors is currently being re-run :runner: Comment updated at 2022-10-25 with changes from be4ebfdcd1ea18e52d1704502fb9a3b0c2292dc3

[github-actions[bot]]

Re-rendered previews from the latest commit:

• See preview of Bookdown here
• See preview of Coursera/Leanpub version here
• Download the preview of .docx file

Updated at 2022-10-25 with changes from 481a74c629bfb9c7bd2e39f484d3e2334d5c0c49