lmp/bb-config: Add variable to debug CI_SCRIPT_DEBUG

[angolini]

This variable will enable bash trace mode to the ci-scripts so we can generate more log in case of a problem.

tested locally with a script that turn on/off the variable:

mkdir -p /tmp/lmp-archive /tmp/lmp-secrets
chmod 777 /tmp/lmp-archive /tmp/lmp-secrets

REPO_DIR=/tmp/lmp-manifest
if [ ! -d "$REPO_DIR" ]; then
    git clone https://github.com/angolini/lmp-manifest.git "$REPO_DIR"
fi
git -C "$REPO_DIR" checkout 13b7dd6a57b714e93cedad7f81fbaebbaf50f01c

docker run --rm -it \
    -v "$(pwd):/ci-scripts" \
    -v "/tmp/lmp-archive:/archive" \
    -v "$REPO_DIR:/repo" \
    -v "/tmp/lmp-secrets:/secrets" \
    -w /repo \
    -e archive=/archive \
    -e DISTRO=lmp \
    -e SOTA_CLIENT=aktualizr-lite \
    -e SOTA_TUF_ROOT_PROVISION=0 \
    -e OSTREE_BRANCHNAME=lmp \
    -e OTA_LITE_TAG=premerge:main \
    -e AKLITE_TAG=premerge \
    -e BITBAKE_EXTRA_ARGS=--continue \
    -e IMAGE=lmp-base-console-image \
    -e MACHINE=beaglebone-yocto \
    -e GIT_URL=https://github.com/angolini/lmp-manifest.git \
    -e GIT_SHA=13b7dd6a57b714e93cedad7f81fbaebbaf50f01c \
    -e GIT_SHA_BASE=9bd8e8ab95fb1829401b6adea9a3ec602f0e4a3e \
    -e GIT_OLD_SHA=9bd8e8ab95fb1829401b6adea9a3ec602f0e4a3e \
    -e CI_SCRIPT_DEBUG=0 \
    -e H_PROJECT=lmp \
    -e H_BUILD=2950 \
    -e H_RUN=build-beaglebone-yocto \
    -e H_RUN_URL=https://api.foundries.io/projects/lmp/builds/2950/runs/build-beaglebone-yocto/ \
    hub.foundries.io/lmp-sdk:next \
    bash -c "git config --global --add safe.directory '*' && bash /ci-scripts/lmp/build.sh"