Added validation of configuration

Fields are being validated right after reading servers details from JSON (when application starts).
Created own annotation to validate server URL with proper requirements.
When invalid details are given application closes.

Signed-off-by: Michal Banka <michal.banka@nokia.com>
Change-Id: I3e476266056ec0fb637f01f9d4d4c63b1f0d1c6a
Issue-ID: AAF-997
16 files changed