feat: add support for instance metadata options

[backjo]

Closes #305

[codecov]

Codecov Report

Merging #305 (c93c041) into master (345ef0c) will decrease coverage by 0.01%.
The diff coverage is 69.38%.

@@            Coverage Diff             @@
##           master     #305      +/-   ##
==========================================
- Coverage   70.06%   70.05%   -0.02%     
==========================================
  Files          19       19              
  Lines        3107     3156      +49     
==========================================
+ Hits         2177     2211      +34     
- Misses        789      804      +15     
  Partials      141      141              

Impacted Files	Coverage Δ
api/v1alpha1/instancegroup_types.go	15.08% <0.00%> (-0.05%)	⬇️
api/v1alpha1/zz_generated.deepcopy.go	0.00% <0.00%> (ø)
controllers/provisioners/eks/scaling/interface.go	0.00% <ø> (ø)
...rollers/provisioners/eks/scaling/launchtemplate.go	87.93% <80.00%> (-0.75%)	⬇️
controllers/provisioners/eks/create.go	89.42% <100.00%> (+0.20%)	⬆️
...ntrollers/provisioners/eks/scaling/launchconfig.go	92.61% <100.00%> (+0.63%)	⬆️
controllers/provisioners/eks/update.go	80.09% <100.00%> (+0.18%)	⬆️

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[eytan-avisror]

LG, added suggestions to move some code to awsprovider

[eytan-avisror]

@backjo nevermind, I see actually in the case of launchtemplate we are placing these constructors within the package.
We can refactor later if it makes sense, for now it's aligned with current patterns.