RFR: SKARA-971: Stop clumping up logs in logstash [v3]

[Erik Joelsson]

> I would like to change how we send logs to logstash so each log message is stored as an individual document. To make this more practical, we need to add some more meta data to each message so we can properly filter them. I suggest adding the following:
> 
> instance_start_time: An ISO_INSTANT time stamp string indicating when this JVM instance was started.
> work_id: A running counter generated ID for each work item, rest request or periodic check, which was previously clumped up in one log message.
> work_item: For work items, store the item toString()

Erik Joelsson has updated the pull request incrementally with one additional commit since the last revision:

  Added simple test of LogContext

-------------

Changes:
  - all: https://git.openjdk.java.net/skara/pull/1120/files
  - new: https://git.openjdk.java.net/skara/pull/1120/files/c257abd2..b82a7bc7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1120&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1120&range=01-02

  Stats: 19 lines in 1 file changed: 19 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/1120.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1120/head:pull/1120

PR: https://git.openjdk.java.net/skara/pull/1120