Support name_override for metrics_version: 2

[jmickey]

When using metrics_version: 2 with the prometheus plugin all metrics are stored in InfluxDB under the measurement name prometheus (see here).

The operator should support a simple method of overriding this name for telegraf sidecars via the name_override property on the prometheus input plugin. I suggest adding an annotation:

telegraf.influxdata.com/metric-v2-name-override

The only way to currently achieve this is to use the telegraf.influxdata.com/inputs annotation to configure the prometheus plugin, and ignore the other annotations.