Add prometheus endpoint

[phavekes]

An example can be found here:

https://medium.com/turkcell/adding-custom-metrics-in-spring-boot-application-for-prometheus-a3893ee86b61

This will add an /actuator/prometheus endpoint, that can be extended with custommetrics

Using spring-boot-starter-actuator and micrometer-registry-prometheus

The metrics for this endpoint:

Total number eduID users
Total number completed app registrations
Total number valid linked accounts (ALA)
Total number valid eidas verifications
Total number valid iDin verifications