Bump version to v3.1.0 & add release notes #3622

Job	Run time
reusable_tests / asan	3m 41s
reusable_docker_tests / docker-test	32m 54s
reusable_tests / coverage	3m 30s
reusable_tests / clang	2m 26s
reusable_tests / docs	52s
reusable_tests / flaky	1m 43s
reusable_tests / python-linter	14s
reusable_tests / multiplatform-tests (Release, ubuntu-22.04)	3m 28s
reusable_tests / tsan	3m 48s
reusable_tests / multiplatform-tests (Release, ubuntu-24.04)	3m 48s
reusable_tests / uncrustify	33s
reusable_tests / multiplatform-tests (Release, windows-2019)	10m 27s
reusable_tests / multiplatform-tests (Release, windows-2022)	12m 16s
reusable_tests / multiplatform-tests (Debug, ubuntu-22.04)	3m 30s
reusable_tests / multiplatform-tests (Debug, ubuntu-24.04)	3m 36s
reusable_tests / multiplatform-tests (Debug, windows-2019)	10m 24s
reusable_tests / multiplatform-tests (Debug, windows-2022)	9m 31s
	1h 46m 41s

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