Add links to grafana from instance detail pages, add grafana provision script

[edlerd]

Done

• add grafana base url to the settings
• add links to grafana from instance detail page if its base url is configured
• add script to setup grafana

QA

1. Run the LXD-UI:
   • On the demo server via the link posted by @webteam-app below. This is only available for PRs created by collaborators of the repo. Ask @mas-who or @edlerd for access.
   • With a local copy of this branch, build and run as described in the docs.
2. Perform the following QA steps:
   • setup o11y stack for lxd:

lxc launch ubuntu:24.04 grafana
curl https://localhost:8407/ui/assets/scripts/setup-grafana.sh --insecure > /tmp/setup-grafana.sh
bash /tmp/setup-grafana.sh grafana default
rm /tmp/setup-grafana.sh

- create the dashboard:
  - open grafana with the link from the script above, then
  - login with admin/admin and chose a new password
  - after login, go to dashboards > new > import
  - enter 19131 and click load
  - confirm the options for prometheus and loki, the click import
- go back to the lxd-ui and ensure the links from instance detail page to "metrics" work fine.

[webteam-app]

Demo

Jenkins

demos.haus

[mas-who]

QA looks good 👍 just got a few comments regarding the script

[mas-who]

Mostly LGTM, just one question about dep version

[mas-who]

LGTM 👍