[REFACTOR] Precise in documentation to add correct namespaces for different context and add it if necessary.

[Miou-zora]

Problem Statement

When creating an example or tests, we're adding elements to the global context of the project which can lead to some problems: have a random class A, demo_setup or Nc with strange namespaces.

Proposed Solution

In all available contexts (examples or tests), add a proper namespace.

Alternative Solutions

Remove tests and examples from doxygen.

Use Cases

Describe how this feature would be used and who would benefit from it:

• Use case 1: Remove some useless class inside global context

Impact

Describe the potential impact of this feature:
None

Implementation Details (optional)

None

Additional Context

None

Related Issues

None