add the x-disable-provenance header for create_alert_rule

[yg265]

Currently the create_alert_rule method provisions the alerting resources using the Alerting Provisioning HTTP API. Could we add the x-disable-provenance header to the requests when creating alerts rules in the API.

https://grafana.com/docs/grafana/latest/alerting/set-up/provision-alerting-resources/

[acjohnson]

I think this seems reasonable, can you also explain the switch from StringIO to BytesIO?

[yg265]

According to python docs, from StringIO import StringIO is no longer supported in python3. https://docs.python.org/3.0/whatsnew/3.0.html
io.StringIO or io.BytesIO are suggested to be used. In this case, it seems that StringIO doesn't support bytes from s3_data_raw.read().