[21128] Update guards and extenstion .h to .hpp in headers

[JesusPoderoso]

Description

This PR is the FastDDS Gen counterpart of this FastDDS PR:

• #[21128] Make all public headers .hpp Fast-DDS#4958

This is part of the set of PRs preparing the new major version 3.x in FastDDS. Consequently, it cannot be backported

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.

[EduPonz]

Missing include guards update in src/main/java/com/eprosima/fastcdr/idl/templates/TypesHeader.stg