Feature Enhancement: add configurability to `exec`

[huanjani]

Currently, exec functionality defaults to logging enabled at the cluster level.
It'd be nice if users could disable logging through Copilot.
That way, if they run commands with sensitive output (like env), the output won't be logged.

Add KMS encryption as well?

[kokuyouwind]

It would be nice to be able to set logging=OVERRIDE as well as disable logging.
In my use case, I would like to keep copilot exec logs separate from normal logs for auditing purposes.