Adding bash "unoffical strict mode" to setup scripts.

[mtauraso]

Change Description

Fixing #494

This will make the setup script definitely not ignore failures. This is the super-opinionated version where we go 110% strict. If this is too brittle for the style of bash we want to be writing, we could shift back toward vanilla bash by:

• Set $IFS back to (space)
• Allow unset variables

If these were removed, the scripts run successfully without the remaining syntax changes

Checklist

• This PR is meant for the lincc-frameworks/python-project-template repo and not a downstream one instead.
• This change is linked to an open issue
• This change includes integration testing, or is small enough to be covered by existing tests

[hombit]

Looks great, thank you