Disable IPsec

IPsec has a significant performance impact.  Disable it for now since is
only partially supported and untested.
Include missing header file
Replace RTEMS objects with custom implementation

Performance analysis revealed that the standard RTEMS objects are a
major bottleneck.  The object get mechanism and attribute checks at
runtime have a significant overhead.  Use a custom implementation for
synchronization primitives.  This drops also the size of the
synchronization primitives considerably.