feat: Add option to hide help text at the end

It can be a little confusing when running stackablectl within scripts. The help text can look like a command didn't run correctly, when it did and the help text is suggesting what to do next:

We could either add an option to disable the help text, or just hide it if CI=true (which we can then export in the getting_started.sh scripts).

For reference, Terraform uses an env var TF_IN_AUTOMATION to control the help text output.

先找出 stackablectl 輸出結尾說明文字的位置，以及它如何處理 CLI 選項或環境變數。將提議的明確選項和以 CI 為基礎的行為與 Terraform 的 TF_IN_AUTOMATION 參考進行比較；完成的標準是，所選的自動化行為能抑制容易造成誤解的說明文字，同時不影響正常的互動式輸出，並且如果選擇該方案，還要更新 getting_started.sh。