JSON payload inside message field of v1.Event

[vigith]

fixes #24

An example run looks something like this

$ k -n default get events -w
+ kubectl -n default get events -w
LAST SEEN   TYPE     REASON                          OBJECT                                              MESSAGE
53s         Normal   EventLifecycleHookReceived      node/ip-10-129-162-131.us-west-2.compute.internal   {"asgName":"iks-system.mpa-play-1.k8s.local","details":"lifecycle hook for event 9ca5bab9-fc84-92be-b133-bbe3dd6e8a30 was received, instance i-05faf90edc56de7d0 will begin processing","ec2InstanceId":"i-05faf90edc56de7d0","eventID":"9ca5bab9-fc84-92be-b133-bbe3dd6e8a30"}
49s         Normal   EventReasonNodeDrainSucceeded   node/ip-10-129-162-131.us-west-2.compute.internal   {"asgName":"iks-system.mpa-play-1.k8s.local","details":"node ip-10-129-162-131.us-west-2.compute.internal has been drained successfully as a response to a termination event","ec2InstanceId":"i-05faf90edc56de7d0","eventID":"9ca5bab9-fc84-92be-b133-bbe3dd6e8a30"}

[codecov]

Codecov Report

Merging #26 into master will decrease coverage by 2.28%.
The diff coverage is 53.16%.

@@            Coverage Diff             @@
##           master      #26      +/-   ##
==========================================
- Coverage   73.64%   71.36%   -2.29%     
==========================================
  Files           8        8              
  Lines         592      646      +54     
==========================================
+ Hits          436      461      +25     
- Misses        107      135      +28     
- Partials       49       50       +1

Impacted Files	Coverage Δ
pkg/service/server.go	62.42% <52.77%> (-3.25%)	⬇️
pkg/service/events.go	80.64% <57.14%> (-7.82%)	⬇️
pkg/service/elbv2.go	84.09% <0%> (+0.75%)	⬆️
pkg/service/elb.go	85% <0%> (+0.78%)	⬆️
pkg/service/autoscaling.go	82% <0%> (+3.42%)	⬆️

---

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[eytan-avisror]

LGTM

Any additional improvements to coverage (if possible) with this PR are welcome