Amazon S3 store update

[munrojm]

AWS profile option added. Also, data will be pulled from S3 index store on query before S3 bucket if possible.

[shyamd]

I pushed some clean up commits. Can you add a test for the new behavior?

[codecov]

Codecov Report

Merging #110 into master will decrease coverage by 0.74%.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##           master     #110      +/-   ##
==========================================
- Coverage   81.57%   80.82%   -0.75%     
==========================================
  Files          21       21              
  Lines        1563     1575      +12     
==========================================
- Hits         1275     1273       -2     
- Misses        288      302      +14     

Impacted Files	Coverage Δ
src/maggma/stores/aws.py	76.27% <85.71%> (-0.15%)	⬇️
src/maggma/stores/mongolike.py	88.48% <0.00%> (-5.76%)	⬇️

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[munrojm]

I pushed some clean up commits. Can you add a test for the new behavior?

Thanks! Sure, no problem.