NR UE: add neighboring cell measurements and measurement report of event A3 This is a rework of MR !2385 (closed), the goal is to add neighboring cell measurements and measurement report of event A3 for NR UE. This MR was tested with: - 3rd-party gNB - 2 OAI-gNB-DUs The neighboring cell measurements and measurement report of event A3 for OAI-UE are working as expected.