added command line interface to be able to manage system repository not ...

...only from UI

this new module provides capabilities to manage system repo from command line, it provides following capabilities (taken from the help menu of the tool):
Available commands:
- exit - quits this command line tool
- help - prints this message
- list-repo - list available repositories
- list-group - list available groups
- list-deployment - list available deployments
- create-group - creates new group
- remove-group - remove existing group
- add-deployment - add new deployment unit
- remove-deployment - remove existing deployment
- create-repo - creates new git repository
- remove-repo - remove existing repository from config only
- add-repo-group - add repository to the group
- remove-repo-group - remove repository from the group

How to use it:
after it is successfully built there will be distribution package in the target folder:kie-config-cli-6.0.0-SNAPSHOT-dist.zip it's enough to unzip it and execute kie-config-cli.sh script. At first it will ask for the folder where .niogit (with system repo) is so it can access the right one that requires modification. If there is no .niogit yet available leaving it empty will allow to create band new setup.

This is initial work and more options can be added if needed. What do you guys think about it?