delete obsolete examples/publisher

boards/airmind/mindpx-v2/default.cmake

boards/atmel/same70xplained/default.cmake

boards/auav/x21/default.cmake

boards/av/x-v1/default.cmake

boards/gumstix/aerocore2/default.cmake

boards/intel/aerofc-v1/default.cmake

boards/intel/aerofc-v1/rtps.cmake

boards/nxp/fmuk66-v3/default.cmake

boards/omnibus/f4sd/default.cmake

boards/px4/fmu-v3/default.cmake

boards/px4/fmu-v3/rtps.cmake

boards/px4/fmu-v3/stackcheck.cmake

boards/px4/fmu-v4/default.cmake

boards/px4/fmu-v4/rtps.cmake

boards/px4/fmu-v4/stackcheck.cmake

boards/px4/fmu-v4pro/default.cmake

boards/px4/fmu-v4pro/rtps.cmake

boards/px4/fmu-v5/default.cmake

boards/px4/fmu-v5/rtps.cmake

boards/px4/fmu-v5/stackcheck.cmake