Remove hard-coded credentials from application.properties

Remove hard-coded credentials from application.properties

Remove hard-coded credentials from application.properties and
use env variables instead.  Note: we still have hard-coded
credentials in dblib.properties and svclogic.properties that
should be changed, but this will require coordinated changes in
sli/core to be able to interpret env variables within properties
files.

Change-Id: I5a31fae6f81233682bee20a5cb531b7f0a21a3a7
Issue-ID: SDNC-1411
Signed-off-by: Dan Timoney <dtimoney@att.com>