[21136] Add XML configuration for FlowControllerDescriptor to 2.x (backport #4893)

[mergify]

Description

This PR is a partial backport from #4837 that brings the XML configuration of the FLow Controller Descriptor List. In 2.x both ThroughtputController and FlowcontrollerDescriptor coexist.

@Mergifyio backport 2.13.x 2.10.x 2.6.x

Contributor Checklist

• Commit messages follow the project guidelines.
• The code follows the style guidelines of this project.
• 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
• Any new/modified methods have been properly documented using Doxygen.
• Any new configuration API has an equivalent XML API (with the corresponding XSD extension)
• [ X Changes are backport compatible: they do NOT break ABI nor change library core behavior.
• 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: [21136] Add XML configuration for FlowControllerDescriptor to 2.x Fast-DDS-docs#793
• 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.

---

This is an automatic backport of pull request #4893 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of e6044e0 has failed:

On branch mergify/bp/2.10.x/pr-4893
Your branch is up to date with 'origin/2.10.x'.

You are currently cherry-picking commit e6044e011.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   include/fastdds/dds/core/policy/QosPolicies.hpp
	modified:   include/fastdds/rtps/attributes/WriterAttributes.h
	modified:   include/fastrtps/xmlparser/XMLParser.h
	modified:   include/fastrtps/xmlparser/XMLParserCommon.h
	modified:   src/cpp/rtps/participant/RTPSParticipantImpl.cpp
	modified:   src/cpp/rtps/xmlparser/XMLElementParser.cpp
	modified:   src/cpp/rtps/xmlparser/XMLParser.cpp
	modified:   src/cpp/rtps/xmlparser/XMLParserCommon.cpp
	modified:   test/unittest/dds/publisher/PublisherTests.cpp
	modified:   test/unittest/xmlparser/XMLElementParserTests.cpp
	modified:   test/unittest/xmlparser/XMLParserTests.cpp
	modified:   test/unittest/xmlparser/test_xml_deprecated.xml
	modified:   test/unittest/xmlparser/test_xml_rooted_deprecated.xml
	modified:   test/unittest/xmlparser/wrapper/XMLParserTest.hpp

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   include/fastdds/rtps/flowcontrol/FlowControllerDescriptor.hpp
	both modified:   resources/xsd/fastRTPS_profiles.xsd
	both modified:   test/unittest/dds/profiles/test_xml_for_string_profile.xml
	both modified:   test/unittest/dds/profiles/test_xml_profile.xml
	both modified:   test/unittest/xmlparser/XMLProfileParserTests.cpp
	both modified:   test/unittest/xmlparser/test_xml_profile.xml
	deleted by us:   test/unittest/xmlparser/test_xml_profile_env_var.xml
	both modified:   versions.md

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[JesusPoderoso]

Docs associated PR:

• #[21136] Add XML configuration for FlowControllerDescriptor to 2.x (backport #793) Fast-DDS-docs#803