~ruther/vhdl-spi-2

ref: cd5b4c89d9709deee774c761e72dd0e6a61ab1a3 vhdl-spi-2/hdl_spi d---------
chore: update cocotb
fix: sck generation

Sampling and changing was offset by one clock,
which is unnecesary. The clock wasn't correct
frequency, ie. divisor 2 led to division by 3
fix: master_ctrl_rst_n shou be used, not master_ctrl_rst, start_clock is split
fix: do not pass rx_serial_o from spi_multiplexor when not enabled
fix: prevent slave ctrl sending X's
feat: add first basic test
chore: few updates
feat: implement masterslave spi switch peripheral
feat: implement initial hdl_spi