[DOC] BACKLOG-1314 - Document the REST calls for Carte (Kettle Path) Part2

What was done:
1) added JMeter tests for the servlets required
2) added comments to the classes
Merge pull request #859 from kolinus/BACKLOG-1314

[DOC] BACKLOG-1314 - Document the REST calls for Carte (Kettle Path) Par...