Add the Interest History service

[pcasteran]

Add the Interest History service : /sapi/v1/lending/union/interestHistory

[codecov]

Codecov Report

Merging #355 (6dfd914) into master (09e883c) will decrease coverage by 0.28%.
The diff coverage is 34.09%.

@@            Coverage Diff             @@
##           master     #355      +/-   ##
==========================================
- Coverage   72.78%   72.49%   -0.29%     
==========================================
  Files          62       63       +1     
  Lines        5868     5912      +44     
==========================================
+ Hits         4271     4286      +15     
- Misses       1181     1203      +22     
- Partials      416      423       +7     

Impacted Files	Coverage Δ
v2/interest_history_service.go	30.95% <30.95%> (ø)
v2/client.go	85.00% <100.00%> (+0.11%)	⬆️

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