Support Spot Instances

[eytan-avisror]

Fixes #35

This PR adds support for spot-instances with the following implementation:

• Recommendation reconciler was added to controller to watch all events, and trigger a reconcile for any event that is with reason SpotRecommendationGiven, the reconciler will reverse lookup the scaling group name from the event's involvedObject.Name, and find the instance group name and namespace in order to trigger it's reconcile.
• aws client (asg) is now needed before context is created (for reverse lookup), we should refactor and move all of the AwsWorker object outside of context instead on a later PR.
• spotPrice can be set manually in the CR, but will always be overridden by recommendations when it exists
• when recommendations become unavailable instance group will switch back to on-demand
• recommendations must follow the format:

# Event Message
{"apiVersion":"v1alpha1","spotPrice":"0.0067", "useSpot": true}
# Event involvedObject.Name = scaling group name
# Event reason = SpotRecommendationGiven

• Also added two additional status fields - usingSpotRecommendations and lifecycle, a printer column was also added for lifecycle.

Testing

• Added unit tests to test recommendations-based and manual setting of spotPrice
• Manually tested create/update in various scenarios

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #36 into master will decrease coverage by 0.29%.
The diff coverage is 70.89%.

@@            Coverage Diff            @@
##           master      #36     +/-   ##
=========================================
- Coverage   70.82%   70.52%   -0.3%     
=========================================
  Files           5        6      +1     
  Lines         682      777     +95     
=========================================
+ Hits          483      548     +65     
- Misses        139      164     +25     
- Partials       60       65      +5

Impacted Files	Coverage Δ
...ontrollers/provisioners/ekscloudformation/types.go	75.28% <100%> (+6.6%)	⬆️
...ollers/provisioners/ekscloudformation/bootstrap.go	83.33% <100%> (ø)	⬆️
...trollers/provisioners/ekscloudformation/helpers.go	60.52% <47.82%> (-5.52%)	⬇️
...rovisioners/ekscloudformation/ekscloudformation.go	79.25% <73.58%> (-2.83%)	⬇️
controllers/provisioners/ekscloudformation/spot.go	74.5% <74.5%> (ø)
...rollers/provisioners/ekscloudformation/strategy.go	52.38% <0%> (+1.05%)	⬆️

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[tekenstam]

LG. May need to add unit tests to new functions to make ccov pass.

[shrinandj]

Fantastic! What the expected json payload if the recommendation is to not use spot-instances?

[eytan-avisror]

@shrinandj

{"apiVersion":"v1alpha1","spotPrice":"", "useSpot": false}

Will be a recommendation to use on-demand (spotPrice is ignored)