During startup retry commands several times before exiting.
Report if the startup was successful or failed.

- the uorb behavior got recently changed so that we now need to clear
  any potential existing messages when we start log streaming.
- ulog_stream_ack should also not use a queue, since the ack is done
  synchonous between mavlink and the logger.

Otherwise these files are added to the NuttX ROMFS build.

Move ros logs dir so that .ulg files are not in the same directory
(mission_test.py:: get_last_log() fails otherwise)

This is to not lose any existing functionality until we have everything
unified.

Also ignore the warning:
error: calling 'system' uses a command processor [cert-env33-c,-warnings-as-errors]

Ensures that clients will get the output of the listener.

By reading sizeof(packet), it could have happened that 2 packets at once
were read, and the second one was then ignored.
This makes sure that only one packet at a time is read.

The other 2 changes are for efficiency.

It was not enough to lock individual accesses to the maps.
For example it could happen that a thread was started and exited very
quickly, before the pthread_t item was inserted into the map, such
that when the cleanup method was called, the thread and pipe fd were not
found (and fd=0=stdin was closed).

The enum change from uint8_t to an int avoids uninitialized bytes,
which led to valgrind warnings (no error though).

The buffer length given to snprintf() is unsigned, so we must check for
an overflow after each call.

This happend for very long printf's (module documentation)

- RPi works
- the rest is not tested, and requires a bit more
  (such as uploading the bin/ directory)

This was printed for all submodules.