Count jobs by skills

Nice day, @chrisshayan  

**Hight-lights of this are:**
* Show line-chart of top 3 of changed skills
* Show top 10 of skills
* Show table of top 3 of changed skills
* 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