boards: arm: stm32f334 nucleo with pyocd and cubeprogrammer as runner

Add the pyocd ant the stm32cubeprogrammer as a runner
of the nucleo_f334r8 platforms,
when the openocd gives an flashing error.
Add the pyocd pack if needed : 'pyocd pack install stm32f334

Signed-off-by: Francois Ramu <francois.ramu@st.com>