* Metrics: remove unused metrics
Metric `M_Grafana_Version` is not used anywhere, nor the mentioned
`M_Grafana_Build_Version`. Seems to be an artefact?
* Metrics: make the naming consistent
* Metrics: add comments to exported vars
* Metrics: use proper naming
Fixes#18110
* tech(routines): move the async logic from notification to alerting notifier
* tech(notification): reduce code dupe
* fix(notification): dont touch the response unless its an error
* feat(alerting): make alerting exeuction async but flow sync
* tech(alerting): remove commented code
* tech(alerting): remove unused code
* tech(alerting): fix typo
* tech(alerting): implement Context on EvalContext
* tech(alerting): wait for all alerts to return
* feat(alerting): dont allow alert responses to cancel
* Revert "feat(alerting): dont allow alert responses to cancel"
This reverts commit 324b006c96687da18a542942f39c10c99119430c.
* feat(alerting): give alerts some time to finish before closing down