Convert the Pyrra generated PrometheusRule manifest into a Prometheus rule group ARM template

[monteiro-renato]

Continuation of #995

Notes:

• Azure has a tool that might work.
• The tool doesn't accept the raw manifest that Pyrra generates. Here's an example input (i.e. we need to extract the group from the Pyrra generated manifest).
• The Interval (in the arm template) needs to be between 1 and 1440 which means that the PrometheusRule manifest can't have intervals lower than 60s. (Property name: Interval, Attempted value: 0.5, Error: '' must be between 1 and 1440. You entered 0.5.)