Support custom step value in dashboard yml for metric queries
Problem to solve
Currently in our monitoring dashboard solution, when we provide queries that aggregate data in say one day at a time and that generates a data point, we should plot the aggregated data by the interval provided by the query.
An example of this can be found in https://dashboards.gitlab.net/d/general-slas/general-slas?orgId=1&from=now-7d&to=now, inside the "Overall SLA over time period - gitlab.com" chart. In this case each data point is shown as 1 day periods, as specified in the query interval was
Currently in https://ops.gitlab.net/gitlab-com/metrics-dogfooding/-/environments/266/metrics?dashboard=.gitlab%2Fdashboards%2Fsla.yml&duration_seconds=604800, the response returns all the data points in the timeframe in the default time window
If we change the panel definitions in some way, we need to provide examples in our documentation as to how this works