Delete Device logic fixed in the account server

Delete Device logic fixed in the account server

1. When a device is deleted, the device ID in each group is removed.
2. The device ID is added only in the resource publish case
3. footnote added

Change-Id: Ifdff14f0f3132a753b2a05cd4e1691657a8b3560
Signed-off-by: yeonghun.nam <yeonghun.nam@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/11137
Reviewed-by: jung seungho <shonest.jung@samsung.com>
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jee Hyeok Kim <jihyeok13.kim@samsung.com>