Changes for 2.13.0 (securedrop-admin as Debian package)

[ChumOfChance]

Fixes #733

With the move to securedrop-admin as a Debian package, there are numerous changes throughout the docs. The paths and commands for most operations have changed.

Please closely check all the paths that have changed. These changes are based on https://github.com/freedomofpress/securedrop/pull/7606#issuecomment-3542424304 and https://github.com/freedomofpress/securedrop-docs/issues/733#issuecomment-3558722529 but it's possible I made a mistake or assumed the wrong path. I think it would be wise to test the documentation steps for many/all of these scenarios.

Note that we will keep a 2.12.10 version of the docs live at least for some time after the 2.13.0 release, as a reference for users using previous versions who are troubleshooting issues before upgrading or need to migrate/restore from backups on older versions.

I've pre-emptively linked to where I expect the blog post announcing 2.13.0 to be posted, assuming it will have more details about the move to a Debian package.

There are also some minor edits for consistent style or errors as I noticed them.

Major changes:

• The cloned securedrop repository is only needed for the initial bootstrapping process. I have changed the Install instructions so that this cloning is done to /~ rather that to ~/Persistent. The repo will not persist after reboot on Tails. I believe it is no longer needed once the securedrop-admin package is installed successfully. This is intended to ease confusion for long-time users who may revert to the habit of trying to run ./securedrop-admin from the ~/Persistent/securedrop directory and reinforced the change.

• I removed the https://docs.securedrop.org/en/stable/admin/maintenance/update_workstations.html page because it is no longer relevant.

• I have re-ordered one part of the Install instructions, moving the initial securedrop-admin trailsbootstrap run on the Admin Workstation, to an earlier step than it would be if following the older instructions closely. This is mostly done to simplify the instructions for setting up a Journalist Workstation.

  In this PR, the instructions to "Onboard Journalists" (create a Journalist Workstation) reference sections of the "Set up the Admin Workstation" page, which is not ideal (this was the case previously as well).

  Eventually I think it would be better to split "Set Up the Admin Workstation" into a page with Admin Workstation-specific instructions, and one with generic instructions for setting up a Tails USB with the secredrop-admin package, since this is done for both Admin Workstations and Journalist Workstations.

  Alternatively, the instructions could be repeated in the "Onboard Journalists" page.

  I'm opting not to make such changes in this PR, instead sticking closer to the status quo, because I think making such change properly coherent would necessitate bigger changes to the entire flow of instructions for installing and deploying.

Test plan

The following pages/sections have instructions or troubleshooting steps that now have different commands and/or paths. These should be checked and in many cases tested.

• [ ] Upgrade instructions 2.12.10 to 2.13.0 (+ Manual Upgrade)
• [ ] Full Fresh Install (many pages)
• [ ] Offboarding
• [ ] Onboarding Admins
• [ ] Onboarding Journalists
• [ ] SSH Over Local Network
• [ ] Tor POW
• [ ] Backup and Restore
• [ ] Backup Workstations
• [ ] Kernel Troubleshooting
• [ ] Rebuild Admin Workstation
• [ ] Updates Over Tor
• [ ] FAQ
• [ ] SecureDrop Admin Utility
• [ ] HTTPS on Source Interface
• [ ] Test the Installation
• [ ] OSSEC Alerts