Add initial provider and prometheus implementation

[dthomson25]

I know that is PR will have some merge conflicts with #168, but they should be minor

[codecov]

Codecov Report

Merging #170 into master will increase coverage by 0.54%.
The diff coverage is 98%.

@@            Coverage Diff             @@
##           master     #170      +/-   ##
==========================================
+ Coverage   81.91%   82.46%   +0.54%     
==========================================
  Files          29       32       +3     
  Lines        2848     2948     +100     
==========================================
+ Hits         2333     2431      +98     
- Misses        379      380       +1     
- Partials      136      137       +1

Impacted Files	Coverage Δ
utils/query/query.go	100% <100%> (ø)
providers/prometheus/prometheus.go	100% <100%> (ø)
utils/evaluate/evaluate.go	80% <80%> (ø)

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