DP-2282: Added commands to get and set gateway id
DP-2282 Add commands to agent to modify gateway id
Merge DP-2282 into development stream
DP-2282 - remove not used method added during merge
DP-2282 fix typo made in method name
DP-2282 fix typo made in test method name
DP-2344 Change timeout of MQTT connector from 1.5s to 20s, and retries count from 30 to 5

Author: Pawel Zwanitaj <pawel.zwanitaj@intel.com>