Loki mixin: alert and recording rules make range interval configurable

[jmichalek132]

Is your feature request related to a problem? Please describe.

In our case we have scrape interval of 1m, however one alert and recording rules in the mixin seem to have hardcoded range interval, examples:
https://github.com/grafana/loki/blob/main/production/loki-mixin/alerts.libsonnet#L10
https://github.com/grafana/loki/blob/main/production/loki-mixin/recording_rules.libsonnet#L8

Describe the solution you'd like

Have a config option for the range interval window in alerts, similar to what is already present for recording rules in mimir mixin and loki mixin. https://github.com/grafana/mimir/blob/main/operations/mimir-mixin/config.libsonnet#L674.

Describe alternatives you've considered
Manually editing the alerts after they are rendered, which kind of defeats the point of mixins imho.

Additional context
https://www.robustperception.io/what-range-should-i-use-with-rate/

As I have raised PRs to fix this in mimir & tempo I can do the same for loki.