Using `-o/--exclude-all-optional` should exclude all optional tasks

[arcivanov]

Currently

-x <task>, --exclude=<task> Exclude optional task dependencies

Using -o/--exclude-all-optional should filter out all optional tasks from the build plan.

[arcivanov]

@mriehl review please

[mriehl]

👍 but make it --exclude-all-optional to avoid ambiguity

[arcivanov]

Will do