Add links to OpenHW Europe and Asia pages on explore WGs

On https://www.eclipse.org/org/workinggroups/explore.php, please add links to the tiles for:

OpenHW Asia - https://www.openhwgroup.org/working-groups/openhw-asia/

OpenHW Europe - https://www.openhwgroup.org/working-groups/openhw-europe/

CC @scorbett