[OLINGO-482] split server processor interfaces + improved dispatching

Change-Id: Ie57a469299e73662838307f1b96b558d3beb723d

Signed-off-by: Christian Amend <chrisam@apache.org>
[OLINGO-482] non-standard HTTP MERGE not to be used in server part

Change-Id: I425dd5b79617ca7f1a56818d0bb106611792ebd5

Signed-off-by: Christian Amend <chrisam@apache.org>