feat: add hook scripts support

environments) will automatically be propagated to your Hurl tests.

When successfully determined, the base url is then [injected as `base_url` variable](https://hurl.dev/docs/templates.html#injecting-variables), and can be freely used in your Hurl scripts with the `{{base_url}}` expression.

### Hook scripts

The Hurl template supports _optional_ **hook scripts** from your project, located in the root directory to perform additional project-specific logic:

* `pre-hurl.sh` is executed **before** running Hurl,

* `post-hurl.sh` is executed **after** running Hurl (whichever the tests status).

    done

  }

  function exec_hook() {

  function maybe_exec_hook() {

    if [[ -f "$1" ]]

    then

      log_info "\\e[33;1m$1\\e[0m hook found: execute"

      if [[ ! -x "$1" ]] && ! chmod +x "$1"

      then

        log_warn "... could not make \\e[33;1m${1}\\e[0m executable: please do it (chmod +x)"

      else

        "$1"

      fi

    fi

  }

  # retrieve server url to test from upstream artifacts ($environment_url variable or 'environment_url.txt' file)

  function eval_env_url() {

    # shellcheck disable=SC2154

    - eval_env_url

  script:

    - mkdir -p -m 777 reports

    - hurl ${TRACE+--verbose} --test --report-junit reports/hurl.xunit.xml $HURL_EXTRA_ARGS $HURL_TEST_FILES

    # maybe execute pre hook

    - maybe_exec_hook "./pre-hurl.sh"

    # run tests

    - hurl ${TRACE+--verbose} --test --report-junit reports/hurl.xunit.xml $HURL_EXTRA_ARGS $HURL_TEST_FILES || rc=$?

    # maybe execute post hook

    - maybe_exec_hook "./post-hurl.sh"

    # exit with return code

    - exit $rc

  artifacts:

    name: "$CI_JOB_NAME artifacts from $CI_PROJECT_NAME on $CI_COMMIT_REF_SLUG"

    when: always