boards: st: stm32h5 boards has openOCD runner from upstream

Define the support /openocd.cfg and the board.cmake to add the openOCD
as runner for the stm32h5x boards.
Note that the openOCD is hack downloaded and build from
from https://github.com/STMicroelectronics/OpenOCD



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