Expose aggregate HTTP server stats (response duration, errors) on prometheus exporter

[mmanes]

Problem

FusionAuth currently exports prometheus metrics for each HTTP URI path invoked, which can be very useful, but can also result in over 1k metric series. Ingesting all of these distinct metrics can get expensive and add overhead to the prometheus datastore. Users may wish to only report on aggregated request statistics, lowering the cost of storage.

Solution

Add an additional prometheus metric that exports HTTP request durations and error counts, aggregated across all URI paths. Scrapers can then be configured to drop the per-URI metrics.

[mmanes]

(internal) PR:

• https://github.com/FusionAuth/fusionauth-app/pull/279
• Add aggregate request metrics and bump version prime-framework/prime-mvc#29