Support changing of group options via REST

The options of a group can now be set by PUT on
'/groups/<group>/options'.

The WebUI was adapted to use this new REST endpoint.

There is a new JSON entity to describe the group options, which is also
included in the GroupInfo, instead of having the options directly in
the GroupInfo.

Change-Id: I5ea30b6ca397a1a377a038bd551092eccabecd40
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
10 files changed