Replace the last of the fastlane lanes with swift tooling

- move more sharable code to CI static methods
- merge `release_to_github` and `prepare_next_release` into one single command as they had dependencies on each other
- remove all traces of ruby and fastlane

ci_scripts/ci_post_xcodebuild.sh

@@ -2,7 +2,8 @@
 
 source ci_common.sh
 
-setup_xcode_cloud_environment
+# Move to the project root
+cd ..
 
 # Xcode Cloud shallow clones the repo. We need to deepen it to fetch tags, commit history and be able to rebase main on develop at the end of releases.
 fetch_unshallow_repository
@@ -14,8 +15,7 @@ swift run -q tools ci upload-dsyms --dsym-path "$CI_ARCHIVE_PATH/dSYMs"
 generate_what_to_test_notes
 
 if [ "$CI_WORKFLOW" = "Release" ]; then
-    bundle exec fastlane release_to_github
-    bundle exec fastlane prepare_next_release
+    swift run -q tools ci release-to-github
 elif [ "$CI_WORKFLOW" = "Nightly" ]; then
     swift run -q tools ci tag-nightly --build-number "$CI_BUILD_NUMBER"
 fi