GitHub Codespaces beta features (#17037)

* Add new articles

* Rename article

* Add secrets content

* Remove permissions statements

* Fix image name

* Fix article name

* Mention GPG verification for Codespaces in "About commit signature verification"

* Add GPG verification content

* Add access and security procedure

* Add 💅

* Rename articles

* Rename the other article

* Rename again

* Okay, rename this one again, too

* Update link

* Start access and security content

* Add 💅

* Mention new functionalities in "Personalizing..."

* Mention new features in "About Codespaces"

* Add 💅

* Fix typos

* Add audit log events

* Fix so many links

* Add 💅

* Add permissions

* Spell access correctly, for once

* Add 💅

* FIX THESE LINKS I SWEAR

* Addd missing )

* Start adding procedure

* update with procedural

* Update content/github/developing-online-with-codespaces/managing-encrypted-secrets-for-codespaces.md

Co-authored-by: Matt Pollard <mattpollard@users.noreply.github.com>

* Update content/github/developing-online-with-codespaces/managing-access-and-security-for-codespaces.md

Co-authored-by: Matt Pollard <mattpollard@users.noreply.github.com>

* Apply suggestions from code review

Committing all reviews ✨

Co-authored-by: Matt Pollard <mattpollard@users.noreply.github.com>

Co-authored-by: Matt Pollard <mattpollard@users.noreply.github.com>
Co-authored-by: Meg Bird <megbird@github.com>

Author: 3 people