[21321] Move Time_t to dds namespace and some *Attributes to xmlparser

[Mario-DL]

Description

This PR:

• Moves some *Attributes to eprosima::fastdds::xmlparser namespace
• Splits Time_hpp in dds::Time_t and rtps::Time_t

Contributor Checklist

• Commit messages follow the project guidelines.
• The code follows the style guidelines of this project.
• 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 Any new/modified methods have been properly documented using Doxygen.
• N/A Any new configuration API has an equivalent XML API (with the corresponding XSD extension)
• NO Changes are backport compatible: they do NOT break ABI nor change library core behavior.
• NO Changes are API compatible.
• New feature has been added to the versions.md file (if applicable).
• New feature has been documented/Current behavior is correctly described in the documentation.
  • Related documentation PR: [21321] Move Time_t to dds namespace and some *Attributes to xmlparser docs Fast-DDS-docs#870
  • Related Python PR: [21321] Split Time_t.i in dds::Time_t and rtps::Time_t  Fast-DDS-python#164
  • Related Shapes Demo PR: [21321] Update references to Time_t and Duration_t ShapesDemo#165
• 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.
• N/A If this is a critical bug fix, backports to the critical-only supported branches have been requested.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.

[JesusPoderoso]

LGTM
(check CI of this commit, commits since then have not changed building code)