Consolidate/reuse JMX implementation from instrumentation

[breedx-splk]

The OpenTelemetry community currently owns two separate JMX metrics implementations.

• The jmx metrics gatherer from this repo
• The JMX metrics insights instrumentation

It was suggested that we should combine these two separate implementations. Most likely, the gatherer should probably reuse functionality from the instrumentation repo. Some investigation will need to be done to see if there are any problems/limitations in this approach. Furthermore, the collector team should be engaged to see if they're getting what they need from the gatherer component and/or if changes would be helpful.

[breedx-splk]

This came up in the Java SIG meeting today.
CC @dehaansa @Mrod1598 @rmfitzpatrick

[rmfitzpatrick]

This would help in delivering #5 and since the jmx receiver in the collector doesn't allow running custom scripts I don't envision much friction as long as we are at effective metric parity.

[SylvainJuge]

We can now consider this as done and close this issue as JMX Scraper is now available as a replacement of JMX Gatherer,
it reuses implementation and metric definitions from instrumentation.