#184 Backend logging library

[NumanFidan]

Added the backed logging library. I choose to add Log4J 2 as logging library because it is:

• easy to use
• one of the most used logging library for Java (around %80 of all Java Apps are using it)
• getting updates constantly

Wiki link is here

I still have some problems with accessing the main/resources path, I need help with it...

@Decappi / @oliviadargel if you want you can merge this branch before the meeting. It is tested on my local machine and works as expected.