src/platforms: move all headers to platforms/common/include/px4_platform_common

and remove the px4_ prefix, except for px4_config.h.

command to update includes:
for k in app.h atomic.h cli.h console_buffer.h defines.h getopt.h i2c.h init.h log.h micro_hal.h module.h module_params.h param.h param_macros.h posix.h sem.h sem.hpp shmem.h shutdown.h tasks.h time.h workqueue.h; do for i in $(grep -rl 'include <px4_'$k src platforms boards); do sed -i 's/#include <px4_'$k'/#include <px4_platform_common\/'$k/ $i; done; done
for in $(grep -rl 'include <px4_config.h' src platforms boards); do sed -i 's/#include <px4_config.h/#include <px4_platform_common\/px4_config.h'/ $i; done

Transitional headers for submodules are added (px4_{defines,log,time}.h)

src/drivers/magnetometer/rm3100/rm3100_i2c.cpp

@@ -37,7 +37,7 @@
  * I2C interface for RM3100
  */
 
-#include <px4_config.h>
+#include <px4_platform_common/px4_config.h>
 
 #include <assert.h>
 #include <debug.h>