Count jobs by skills

Nice day, @chrisshayan  

Hight-lights of this are:
1. One call to ES server to get
* Count all technical jobs: "java", ".net", "dba"...
* Count all technical jobs of a term: "java" / ".net" / "dba" ...
* Get histogram of skills: "spring", "jpa", ...
* Apply JDK 8 streaming API in parallel way
2. Show line-chart of top 3 of changed skills
3. Show top 10 of skills
4. Show table of top 3 of changed skills