enhance & align jetty jmx metrics

[SylvainJuge]

• rename and attempt to align existing jetty jmx metrics to semconv, this is a breaking change as it renames and modifies the metric attributes
• remove the jetty.logging.LoggerCount metric for the number of registered loggers as it's probably not very relevant
• integration test with jetty 9 to jetty 12
• add support for jetty 12 with different metrics & metrics attributes due to jetty implementation details

The current implementation maps all the MBean parameters to metric attributes, and the main problem here is that we have a lot of "technical" attributes that do not provide any value to the end user, can cause high cardinality and are just artifacts of the underlying implementation.

I have opened #14070 to discuss the ways we could solve this issue.
I think progress on this PR will be blocked until we solve this issue first.

Update (1): ignoring technical MBean parameter is fine when there is only a single MBean instance, which is the case by default. We can however decide to avoid producing any potentially invalid metric by removing most of the gauge metrics.

Update (2): we decided in the 2025-06-26 SIG meeting to remove any problematic metric, we can always add them later if needed, or add a feature to handle them properly.
Also, most if not all of the impacted metrics are for Jetty 11 and earlier, which are EOL in Jetty documentation. Those metrics do not have an equivalent for Jetty 12 yet.

[SylvainJuge]

following 2025-06-26 SIG meeting, jetty metrics have been simplified to only include the ones that are not susceptible to unpredictable aggregation (gauges with multiple mbean instances as documented in this other PR).

[trask]

cc @PeterF778 @robsunday