feat(cocotb): add nvc and vhdl2008 support to cocotb

This commit adds the NVC simulator support to the FWK cocotb tool. NVC is an open source simulator. The main advantage wrt. GHDL is speed and the ability to access custom port types (e.g. t_32b_slv_vector).

This commit also adds VHDL2008 support to the cocotb tool.