Read config from environment variables

The application configuration should be read from command line options
as well as from environment variables. The priority: cmd-line over env
over defaults.

Change-Id: I785fd1fbaf66f3eab84a162f037153f1688ed791
Issue-ID: DCAEGEN2-748
Signed-off-by: Piotr Jaszczyk <piotr.jaszczyk@nokia.com>
5 files changed