Add support for Zabbix Discovery queries

[dd00f]

DiscoveryQuery : Used to discover a list of JMX beans matching a specific naming pattern.
Used with the Zabbix server.

For example, the following discovery rule :

<discoveryQuery 
   objectName="java.lang:type=GarbageCollector,name=*" 
   attributes="name,type" 
   resultAlias="discovery[garbageCollector]" 
   collectIntervalInSeconds="300"/>

<query objectName="java.lang:type=GarbageCollector,name=*"
   attributes="CollectionTime,CollectionCount"
   resultAlias="discovery[GarbageCollector.%name%.#attribute#]" />

May yield the following discovery output (formatted for readability) :

{"data":[
  {"{#NAME}":"PS Scavenge","{#TYPE}":"GarbageCollector"},
  {"{#NAME}":"PS MarkSweep","{#TYPE}":"GarbageCollector"}
]}

On the Zabbix side, create a "Discovery Rule" of type "Zabbix trapper"
with a "Key" that matches the result alias. You can then create "Item prototypes" that use the values.

Sample Zabbix configuration that matches the example above :

Discovery rule :
Name : Discover Garbage Collectors
Key : discovery[garbageCollector]

Item Prototype
Name : Object {#TYPE} named {#NAME}
Key : discovery[{#TYPE}.{#NAME}.CollectionTime]

Item Prototype
Name : Object {#TYPE} named {#NAME}
Key : discovery[{#TYPE}.{#NAME}.CollectionCount]