Add REST endpoints to get/set default user preferences

GET on /config/server/preferences returns the default user preferences
while PUT on /config/server/preferences allows administrators to set
them.

These REST endpoints only support the options that are stored in the
All-Users repository. This means at the moment only for the 'My' menu
entries a default can be set.

Change-Id: I064dd8baaa798b979938be6cdc2a36ab249bb694
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
5 files changed