Reduce image size of containers

Reduce image size of containers

CIA project goal is to reduce image size of container and make the
container multi architecture.

Portal images are already multi architecure ready and portal-wms and
portal-db are also done in an efficient way.

Portal-app and portal-sdk although can be shrinked, using multi stage
docker builds.

This commit allow a noticeable shrink for both of them:

from 708Mb to 298Mb for portal-app and from 388Mb to 257Mb for
portal-sdk.

Change-Id: Id5cca8b78d0d9ee1724259dab40b7ccff910c628
Issue-ID: INT-939
Issue-ID: INT-922
Issue-ID: INT-881
Issue-ID: INT-925
Issue-ID: INT-936
Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>