.github: Update top-level with shared actions, clean-up

[gastmaier]

PR Description

Use the ci shared-actions, remove old dependencies.
We can squash all commits until 6.12-y head instead.
file to be reviewed: top-level.yml , added the devicetree action

@pamolloy , you may as well wait a little for the deploy to cloudsmith step

key points:
ensure

          curl -s -H "Authorization: Bearer ${{ secrets.GITHUB_TOKEN }}" -L -o runner_env.sh \
            https://raw.githubusercontent.com/analogdevicesinc/linux/ci/ci/runner_env.sh
          source ./runner_env.sh

Check if the adsp devicetrees are globed in the compile_devicetrees step.

Check if all steps are using the shared action

PR Type

• Bug fix (a change that fixes an issue)
• New feature (a change that adds new functionality)
• Breaking change (a change that affects other repos or cause CIs to fail)

PR Checklist

• I have conducted a self-review of my own code changes
• I have tested the changes on the relevant hardware
• I have updated the documentation outside this repo accordingly (if there is the case)