DEVX-78 migrate category sync statistics

[lojzatran]

Summary

JIRA: https://commercetools.atlassian.net/browse/DEVX-78

Note:

The following classes were already migrated in the previous PRs:

src/test/java/com/commercetools/sync/sdk2/commons/helpers/BaseSyncStatisticsTest.java
src/test/java/com/commercetools/sync/sdk2/commons/asserts/statistics/AssertionsForStatistics.java

[codecov-commenter]

Codecov Report

Merging #968 (17b797a) into DEVX-76_migrate_CategoryCustomActionBuilder (5368a2f) will increase coverage by 0.00%.
The diff coverage is 95.65%.

@@                              Coverage Diff                               @@
##             DEVX-76_migrate_CategoryCustomActionBuilder     #968   +/-   ##
==============================================================================
  Coverage                                          95.61%   95.61%           
- Complexity                                          3942     3950    +8     
==============================================================================
  Files                                                343      344    +1     
  Lines                                              11516    11539   +23     
  Branches                                             697      698    +1     
==============================================================================
+ Hits                                               11011    11033   +22     
- Misses                                               400      401    +1     
  Partials                                             105      105           

Impacted Files	Coverage Δ
...dk2/categories/helpers/CategorySyncStatistics.java	95.65% <95.65%> (ø)