Move performance tests to separate project

[lookeypl]

Right now performance tests of specific modules are kept together with unit tests. Unit tests should be performed fast, because doing precise performance tests might take a while

• Create projects ~~nfCommonPerfTest~~ and nfCorePerfTest
• ~~Move existing performance tests to these projects~~
• Make sure that all tests are precise:
  • Each test should check how specific module works for different amount of data
  • Each test for each amount of data should calculate an average time to make the results precise
• ~~Update tests.py to launch performance tests only when necessary (with option -p/--perf or similar)~~
• Save test results in CSV (or similar format).

[lookeypl]

Since Latch utility is now used in more than one project, it has been moved to nfCommon: https://review.gerrithub.io/#/c/232264/

Creation of nfCommonPerfTest, moves ThreadPoolPerformance to nfCommonPerfTest as well: https://review.gerrithub.io/#/c/231317/

I had Packer performance tests lying around on my hard drive, so I revised them and added as well: https://review.gerrithub.io/#/c/231318/

[lookeypl]

Freeing the task - there are more important issues right now for me. Anyone who wants to complete it, feel free to take it.