Ask on package rebuild

[amd-vserbu]

The package-deb.sh and package-rpm.sh scripts run a full clean build, including the static shell, starting by removing any previous build.

This patch asks the user if they really want to run the rebuild, to prevent accidental removals.

If the script is run non-interactively (stdin is not a terminal), this question is skipped.

This patch also adds early checks for v++ in path (Vivado/Vitis sourced) and for the smbus, so that the build fails early with descriptive errors if the user has not satisfied the prerequisites for build.

[JOOpdenhoevel]

I would advocate for an explicit "non-interactive" or "always say yes" option. You never know in what kinds of situations such a script is executed, so only using the test -t check might lead to situations where the script is actually executed non-interactively, but it doesn't look like it.

[amd-vserbu]

@JOOpdenhoevel Fair enough. Added --noninteractive to the scripts.

[JOOpdenhoevel]

LGTM

[hpc-aulmamei]

lgtm. merging