Upgrade last remaining instances on D9

Last instances of D9

• admin-eguide - web team will look into it, no ETA yet
• sg-cms-1 - these are pending 3rd party contractors, no change expected soon, can be moved behind SSO
• sg-cms-2
• sg-cms-3
• atlas-voting atlas-voting.web.cern.ch
• test-sa-voting-site staff-association-elections.web.cern.ch
• aion-project

Start by updating the following, which requires no coordination with site owners:

• atlas-voting atlas-voting.web.cern.ch
• test-sa-voting-site staff-association-elections.web.cern.ch
• aion-project

Coordination with site owner needed:

• sg-cms-1 - these are pending 3rd party contractors, no change expected soon, can be moved behind SSO
• sg-cms-2
• sg-cms-3

admin-eguide will likely be moved to Git Pages and decommissioned, to be ignored for now