Update ros2.repos and docs for 4.5 branch

[srmainwaring]

• AP_DDS: replace ref interface with binary interface in uxr create entity methods ardupilot#27145 removes the need for the micro_ros_agent ref file: dds_xrce_profile.xml. This simplifies installing and configuring the ROS 2 node, but is a breaking change.

• The new 4.5 branch in this repo is intended to match the 4.5.x series releases of ArduCopter, ArduPlane etc, and retains the ref file. The documentation and ros2.repos file of the 4.5 branch need to be updated to be consistent.

Tasks

• Update ros2.repos files
• Update documentation
• Update wiki entry (add note explaining procedure for 4.5 release vs master).