cli: Replace printf_err with BT_CLI_LOGE_APPEND_CAUSE

cli: Replace printf_err with BT_CLI_LOGE_APPEND_CAUSE

The printf_err macro is currently used to report an error in the CLI.
However, we now have a proper error reporting framework.  This patches
makes the CLI use it.

All usages of printf_err are replaced with BT_CLI_LOGE_APPEND_CAUSE.

All usages of print_err_oom are replaced with a new macro that calls
BT_CLI_LOGE_APPEND_CAUSE("Out of memory.").

I haven't tested all the errors paths to make sure they worked well, but
here are some examples of the result:

    $ babeltrace2 convert --run-args --legault

    ERROR:    [Babeltrace CLI] (/home/smarchi/src/babeltrace/src/cli/babeltrace2.c:2874)
      Command-line error: retcode=1
    CAUSED BY [Babeltrace CLI] (/home/smarchi/src/babeltrace/src/cli/babeltrace2-cfg-cli-args.c:3621)
      While parsing command-line options, at option --legault: unknown option

    $ babeltrace2 convert --run-args -i salut

    ERROR:    [Babeltrace CLI] (/home/smarchi/src/babeltrace/src/cli/babeltrace2.c:2874)
      Command-line error: retcode=1
    CAUSED BY [Babeltrace CLI] (/home/smarchi/src/babeltrace/src/cli/babeltrace2-cfg-cli-args.c:3834)
      Unknown legacy input format:
          salut

Change-Id: I891c0518c66f61a62fd2e73cf3c438b622aabd9a
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1692
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>
Tested-by: jenkins <jenkins@lttng.org>