ci: new add-on passes AppInspect

[artemrys]

Issue number: N/A

PR Type

What kind of change does this PR introduce?

• Feature
• Bug Fix
• Refactoring (no functional or API changes)
• Documentation Update
• Maintenance (dependency updates, CI, etc.)

Summary

Changes

Introduce a new test to verify that the new add-on (init -> build -> package) passes Splunk's AppInspect checks.

It contains one hack

echo "# Binary File Declaration\n\nIgnoring lib/charset_normalizer/md.cpython-37m-x86_64-linux-gnu.so" > demo_addon_for_splunk/package/README.txt

to make sure we actually pass AppInspect checks.

We will need to follow up on it with the team and see how this can be solved long-term.

User experience

N/A

Checklist

If an item doesn't apply to your changes, leave it unchecked.

• I have performed a self-review of this change according to the development guidelines
• Tests have been added/modified to cover the changes (testing doc)
• Changes are documented
• PR title and description follows the contributing principles