Add installation mode to use snapshot image

Installation mode dev added to use the snapshot images for rApp Manager and DME Participant.

Issue-ID: NONRTRIC-930
Signed-off-by: aravind.est <aravindhan.a@est.tech>
Change-Id: Ibb3bc6978e6ec7f1bb3bc448d54b52632fe7dc39
3 files changed