PowerControl over ssh

[baz2142]

Description of changes

This PR introduces:

• The package PowerControl, which provides scripts to power control the host via ssh;
• Refactored ssh keys generation and sharing on Lenovo X1 target
• Add poweroff and reboot buttons on Lenovo X1 host in GUI

Works only on debug builds so far -- we need ssh-connection in release builds as well

Checklist for things done

• Summary of the proposed changes in the PR description
• More detailed description in the commit message(s)
• Commits are squashed into relevant entities - avoid a lot of minimal dev time commits in the PR
• Contribution guidelines followed
• Ghaf documentation updated with the commit - https://tiiuae.github.io/ghaf/
• PR linked to architecture documentation and requirement(s) (ticket id)
• Test procedure described (or includes tests). Select one or more:
  • Tested on Lenovo X1 x86_64
  • Tested on Jetson Orin NX or AGX aarch64
  • Tested on Polarfire riscv64
• Author has run nix flake check --accept-flake-config and it passes
• All automatic Github Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing

Build debug target on Lenovo X1, run it, you will see two buttons in GUI VM next to applications icons: PowerOff and Reboot. They should make described actions

[brianmcgillion]

your main branch is 68 commits behind ghaf main, so a sync and rebase before a request to merge would be needed

[vilvo]

Would you also please edit the description to follow https://github.com/tiiuae/ghaf/blob/main/.github/pull_request_template.md ?
Easier for reviewers to evaluate how checklist items have been considered.

[vilvo]

@leivos-unikie - can you please test this is on Lenovo X1?

[leivos-unikie]

• ci-test-automation test suite passed
• Apps launch by clicking the icons
• Poweroff and Reboot buttons work

[baz2142]

@vilvo, time to merge? @leivos-unikie has approved

[brianmcgillion]

can you resolve the merge conflict, by rebase and it can go in