Update QtBinarySizeBot database schema to include useful shas

The Qt Binary Size Bot currently creates data points with an array of shas included in the coin integration. While useful in a vacuum, this format cannot be used in grafana to create links to gerrit or coin, since no array handling is available.

Either update the schema to write different data for "commit_url" in a useful format, or add a new tag that contains the link to the integration itself.