Add CallbackNodeStatus

[odow]

Test will fail until #161 is merged, so this is just a draft.

Closes #160

Also address #146

[codecov]

Codecov Report

Merging #162 (59265eb) into master (6c8fb69) will increase coverage by 0.03%.
The diff coverage is 86.36%.

@@            Coverage Diff             @@
##           master     #162      +/-   ##
==========================================
+ Coverage   84.39%   84.43%   +0.03%     
==========================================
  Files           8        8              
  Lines        1474     1497      +23     
==========================================
+ Hits         1244     1264      +20     
- Misses        230      233       +3     

Impacted Files	Coverage Δ
src/MOI_wrapper/MOI_callbacks.jl	96.47% <86.36%> (-3.53%)	⬇️
src/MOI_wrapper/infeasibility_certificates.jl	91.66% <0.00%> (+0.17%)	⬆️

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