Honor labels option

Hello,

I am trying to scrape pushgateway using PodMonitoring object. In general it works but it does relabel `job` and `instance` labels.

To prevent relabeling, [one can specify](https://github.com/prometheus/pushgateway#about-the-job-and-instance-labels) `honor_labels: true` in scrape config but this is currently not possible with PodMonitoring object.

Can you please add an option to enable configuration of `honor_labels`?