Grafana Agent Operator - Support creating rules for Loki

[EStork09]

Similar to #1986 and #2604 there is now support to configure Mimir's ruler with rules from the prom-operator CRDs. Could we use the same CRDs to also generate Loki rules as well?

[rfratto]

This should definitely be possible, at least as a Flow component in the same style of #2604. It looks like Loki's ruler API is mostly the same, but uses a different endpoint so it wouldn't work out of the box with the existing mimir.rules.kubernetes component.

[EStork09]

Yeah I almost thought about just basically copying that PR and renaming everything to loki and seeing how far I could get with it before people realized I had no idea what I was actually doing