Allow relabeling for promitor-agent-resource-discovery servicemonitor

[afourneau]

Hey,

Would it be possible to add relabeling for the service monitor of the agent discovery, like it's done for the agent scrapper:

charts/promitor-agent-scraper/templates/servicemonitor.yaml

Lines 30 to 33 in 14c11c9

	{{- if .Values.metricSinks.prometheusScrapingEndpoint.serviceMonitor.relabelings }}
	relabelings:
	{{- toYaml .Values.metricSinks.prometheusScrapingEndpoint.serviceMonitor.relabelings | nindent 4 }}
	{{- end }}

Thanks.

[tomkerkhove]

I'm open to contributions!