Reload the cron container instead of restarting it

According to the current execution flow of `cron-command`, whenever any new cron job is added, it restarts the `easyengine/cron` container to accommodate the new changes. This can disrupt the cycle of already running cron-jobs.

For example, if a job is running every 10 minutes and had completed say 9 minutes before restart was executed, then it's time will start from zero again. Thus, the executing cron cycles could get a little affected by this.

A reloading signal or a HUP signal to refresh and accommodate the new changes is required to replace the current restart method.

`cron-command` の現在の実行フローと、新しいジョブが追加されたときに `easyengine/cron` コンテナを再起動する箇所を追跡します。コンテナが reload または HUP シグナルをどのように処理するかを確認し、ジョブの追加によって設定が更新され、すでに実行中の cron-job サイクルがリセットされないことを検証します。

索引モデルが issue の本文から書いたものです。