Add page and application-level analytics

[craig-willis]

Currently we only track usage via index.html. Use Google Analytics SPA techniques to instrument relevant actions/pages on the application. For example:

• Catalog page
• Applications page
• Adding, starting, stopping individual applications

If possible.

[bodom0015]

For a more granular approach to exporting these metrics, we might also consider revisiting Prometheus (outside of the context of federation).

They offer a Go client library that we can leverage to export metrics from the Workbench apiserver: https://prometheus.io/docs/guides/go-application/

[bodom0015]

Related to #278