* onnx: fix cmake commands list
Signed-off-by: Artur Wojcik <artur.wojcik@intel.com>

* onnx: change exception name to UnknownOperator
Signed-off-by: Artur Wojcik <artur.wojcik@intel.com>

* onnx: rename ops_bridge class
Signed-off-by: Artur Wojcik <artur.wojcik@intel.com>

* onnx: initial opset versions
Signed-off-by: Artur Wojcik <artur.wojcik@intel.com>

* onnx: check operator availability
Signed-off-by: Artur Wojcik <artur.wojcik@intel.com>

* onnx: opset versions - after reivew changes
Signed-off-by: Artur Wojcik <artur.wojcik@intel.com>

* onnx: fix doxygen comment fromat