@MetricOptions to allow filtering AbstractMethodTagger beans to apply to metrics

[hrothwell]

Follow up to #753

• New annotation MetricOptions to hold metadata for additional information that might be used in building metrics
  • includes list of taggers for class types to apply to the published metric.
  • Note: I was unsure on how to best implement a "don't filter any beans, apply everything" so I currently opted for treating an empty array as no filtering, but I don't think this should be a final solution. Looking for more input about it.
• Add new tests showing filtering is applied correctly
• Was planning on updating documentation after input on how to go forward with the issue listed above and as a TODO

[graemerocher]

you can add a containers check for the annotation member and if it is empty then disable all taggers I guess

[hrothwell]

I'm not sure I follow what you are referring to, but it sounds like disable all taggers if taggers is empty?

The idea I am going back and forth on is how do we differentiate "use all taggers" without needing to specify all additional taggers? Ideally what I was hoping for was something like:

taggers == null --> no filtering done, all taggers get appliedf
taggers == empty array --> filtering is enabled, this filters out all taggers effectively disabling them
taggers == populated array --> filters just to taggers in populated array

[hrothwell]

I added a helper annotation value as a different option also, not sure what is most ideal really

[graemerocher]

ok looks fine can you update the javadoc and remove the TODO

[graemerocher]

ok looks fine can you update the javadoc and remove the TODO

[hrothwell]

Updated docs + added @Experimental per request

[graemerocher]

Thanks for the contribution!