main/sorcery: Provide log messages when a wizard does not support an operation

If a sorcery wizard does not support one of the 'optional' CRUD
operations (namely the CUD), log a WARNING message so we are aware of
why the operation failed. This also removes an assert in this case, as
the CUD operation may have been triggered by an external system, in
which case it is not a programming error but a configuration error.

Change-Id: Ifecd9df946d9deaa86235257b49c6e5e24423b53