[#161] Add report issue and clone link in the configuration

Add two new optional configurations:
 - blue.client.issues-url: link to report issues
 - blue.client.clone-url: where the code can be found.

The client side configuration manager has been improve.
All configurations stored in AppConfig is now automatically available in the constant
config.
Merge pull request #164 from tdurieux/config-report-url

[#161] Add report issue and clone link in the configuration