Add micrometer instrumentation

[mfvanek]

Consider adding metrics in prometheus format.
We should use Micrometer 1.9.12 (or higher but compatible with Spring Boot 2.7.x)

[mfvanek]

For example see

• https:/micrometer-metrics/micrometer/blob/main/micrometer-core/src/main/java/io/micrometer/core/instrument/binder/tomcat/TomcatMetrics.java
• https:/spring-projects/spring-boot/blob/main/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/tomcat/TomcatMetricsBinder.java
• https:/spring-projects/spring-boot/blob/main/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/tomcat/TomcatMetricsAutoConfiguration.java

The most important thing here is that metrics can't be binded during bean creation. It leads to circular dependency. Should use this pattern

    @Override
    public void onApplicationEvent(ApplicationStartedEvent event) {
...
        this.tomcatMetrics.bindTo(this.meterRegistry);
    }

[mfvanek]

After migration to Spring Boot 3. Consider to use Micrometer Observation