Integrate ccglib in the form of a new BeamFormerCCGKernel

This kernel uses ccglib to perform the beamforming (a GEMM on complex numbers). Due to differences in the input and output shapes and data types (complex or scalar with complex axis somewhere else), the kernel is not a true drop-in replacement for the BeamFormerKernel or BeamFormerWMMAKernel. A test (tBeamFormerCCGKernel) and benchmark (bBeamFormerCCGKernel) have been added as well. Both work only with 16-bit input data.