feat(components): add observability services starter

[squakez]

In this PR we're adding the starter for the component.

[squakez]

@davsclaus @Croway I've tested the component with a servlet, and the clash, although did not produce any error, really was not allowing the exposure of the metrics. Tested changing the component default, instead, makes it work:

$ curl http://localhost:8080/camel/greet
Hello World
$ curl http://localhost:8080/observe/metrics
# HELP application_ready_time_seconds Time taken for the application to be ready to service requests
# TYPE application_ready_time_seconds gauge
...

It makes sense to move the base default to /observe/, hence having /observe/metrics, /observe/health, ... I'm changing it also in the core component.

[davsclaus]

Yes observe is a good name

And about servlet then it was before we had platform-http on SB. So its not recommended to use. But IMHO lets avoid using camel as end users may use that too.

[squakez]

Default changed also in core: apache/camel#16302