Removal of non_root_user test

[macaktom]

Description

Removal of non_root_user test (removed test, spec test and documentation for this test). Other parts concerning Falco will be removed in another PR. PR for Falco will be created, after this one is merged.

Issues:

Refs: #1891

How has this been tested:

To test everything I run workload tests and all spec tests.

Types of changes:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist:

Documentation

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• No updates required.

Code Review

• Does the test handle fatal exceptions, ie. rescue block

Issue

• Tasks in issue are checked off

[martin-mat]

there are still non_root_user references in
src/tasks/workload/configuration.cr (a todo comment only though)
docs/falco-config.md

but those are mostly falco-related and will be removed along with falco removal.

Thus LGTM.

[HashNuke]

LGTM ~! 👍