feat: Implement colored output (with `NO_COLOR` support)

Colours sould only be enabled when the terminal supports them.
For example, when redirecting output or piping to cat, there should be no escape sequences.

I believe there needs to be a condition around the pretty method (or maybe it should be handled by tracing_subscriber::fmt):

https://github.com/stackabletech/stackable-cockpit/blob/fe37d494359d91e32ae309a9f6d382b4a486c5a0/rust/stackablectl/src/main.rs#L31

Examples:

stackablectl --log-level=DEBUG stack list > /tmp/stackablectl.stdout       # plain redirect
stackablectl --log-level=DEBUG stack list | cat > /tmp/stackablectl.stdout # pipe through cat
TERM= stackablectl --log-level=DEBUG stack list > /tmp/stackablectl.stdout # explicitly set TERM to nothing

If I open it in VIM, it looks like this:

從 rust/stackablectl/src/main.rs 中連結的 pretty 方法附近開始，比較 tracing_subscriber::fmt 是否應負責終端機偵測。使用重新導向和管線輸出執行列出的 stackablectl 命令，包括 TERM 為空的情況，並確認非互動式輸出不包含逸出序列，而支援的終端機輸出仍保持彩色，且遵循 NO_COLOR。