Extended delta API

[fo-code]

I implemented the new delta extension of the Forensics API Plugin for Git. The code delta can now be calculated between two Jenkins builds.

[uhafner]

Sorry that I did not spot this problem before...

That means forensics-api need another change:

public Optional<Delta> calculateDelta(final Run<?, ?> build, final Run<?, ?> referenceBuild,
             final String scmKeyFilter, final FilteredLog logger) {

Do we need the other methods still in the API? Then we can remove them and ignore the errors in RevAPI.

[codecov]

Codecov Report

Merging #440 (9f947c9) into master (cc1156b) will increase coverage by 0.03%.
The diff coverage is 85.71%.

❗ Current head 9f947c9 differs from pull request most recent head 864bf4b. Consider uploading reports for the commit 864bf4b to get more accurate results

@@             Coverage Diff              @@
##             master     #440      +/-   ##
============================================
+ Coverage     81.94%   81.97%   +0.03%     
- Complexity      194      196       +2     
============================================
  Files            26       26              
  Lines           781      788       +7     
  Branches         82       83       +1     
============================================
+ Hits            640      646       +6     
  Misses          110      110              
- Partials         31       32       +1     

Impacted Files	Coverage Δ
...lugins/forensics/git/delta/GitDeltaCalculator.java	89.47% <85.71%> (-2.20%)	⬇️

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