[21129] Migrate fastrtps namespace to fastdds

[elianalf]

Description

This PR migrates fastrtps namespace to fastdds.
Related Fast DDS PR:

• [21129] Migrate fastrtps namespace to fastdds Fast-DDS#4898

Contributor Checklist

• Commit messages follow the project guidelines.
• N/A Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally
• N/A New feature has been documented/Current behavior is correctly described in the documentation.
• N/A Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.