[21226] Improve CI workflows in master, and branching model refactor

[JesusPoderoso]

Description

This PR improves the CI workflows, making them as similar as possible to the Fast DDS workflows.
It also introduces a braching model refactor, similiar as the performed in Fast DDS repository.

Note: While backporting this PR, please ensure the following changes:

• Remove nightly jobs
• Update ubuntu-ci.yml file with the proper fallback branches
• Change fastdds.repos to fastrtps.repos
• 3.3.x and 3.2.x requires both 1.1.x and 2.x Fast CDR branches to be tested
• 2.5.x requires only jdk11
• 2.1.x requires building on ubuntu-20.04, and only jdk11

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.
• 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.