[refactor] Split tsdb package out into separate repo about xephon-b HOT 3 CLOSED

the problem is currently tsdb-proxy code lies in two folders, cmd/tsdb and pkg/tsdb and I want a structure like

cmd
  main.go
pkg
  cmd 
  kairosdb
  influxdb

may need some tweak like http://stackoverflow.com/questions/19954485/extract-multiple-directories-using-git-filter-branch, simply split one branch may not work for me. Also the official doc could help https://git-scm.com/docs/git-filter-branch

from xephon-b.

git filter-branch --index-filter 'git rm -r --cached --ignore-unmatch cmd/xb cmd/xephon-b' master
git filter-branch --index-filter 'git rm -r --cached --ignore-unmatch pkg/cmd pkg/config pkg/generator pkg/loader pkg/monitor pkg/simulator' master

from xephon-b.

Another possible solution is to backup current master branch and only keeps those tsdb independent part, like logging, some basic command.

• migrate the common entity structs to tsdb-proxy
• remove simulator, generator and loader, since they didn't have much code ...
• a lot of scripts can be removed as well, since they are all used to setup the tsdb

xephon-b can focus more on the following in order to aid the https://github.com/at15/hadoop-spark-perf project while waiting for https://github.com/dyweb/gommon

• keep record of experiments config, it's kind of like popper, but I'd like to put things in database
• collect cpu metrics, I don't know if perf have programmatic API

from xephon-b.