Introduce new API for VLAN tagged frames

The GTSB HAL introduces a different way to handle VLAN tagged frames than existing HALs use. In order to support this new design as well as the existing implementations, a distinct API for handling VLAN tagged frames needs to be introduced:

• When receiving frames, the VLAN tag information will via the frame properties structure
• For sending VLAN tagged frames, a new function to allocate a vlan tagged frame buffer is defined
• The frame buffer descriptor structure is added a pointer to the payload part of the frame (starting with ether type)

Along with this modification some of the data structures are reorganized and renamed.