DP-3122 - Change config loading strategy

DP-3122 Fix configuration files

DP-3122 Add writing to user configuration instead global

DP-3122 Fix configuration files to default

Signed-off-by: Pawel Zwanitaj <pawel.zwanitaj@intel.com>
DP-3115 Add -C / --config flag to agent and admin

Signed-off-by: Pawel Zwanitaj <pawel.zwanitaj@intel.com>
DP-3282 Logging MQTT connected and close connection events.

DP-3282 Saving bindings and restoring subscription to topics after MQTT reconnection. Detaching old event handlers for that topic before applying new handler.

Signed-off-by: Marek Tomczewski <marek.tomczewski@intel.com>
DP-3122 User config is empty by default. Only example is provided in comment.