Build prometheus configuration dynamically

[keithf4]

While the targets for prometheus can be dynamically handled, the rest of the configuration must be in a single file. This can make it challenging to support a wider variety of configurations.

See if we can have the service file build a configuration file from other files, similar to how the query file is built for the exporters. Unlike that one, the order may matter. Would have to see if multiples of the same configuration setting can be used in the same file (IE. multiple scrape_config sections)

[keithf4]

Will not be doing a dynamically built prometheus configuration file in pgMonitor at this time.