support for WString across all generators

[dirk-thomas]

Follow up of #346.

[dirk-thomas]

• Linux
  • unrelated test failures addressed in Update tests that were missed during switch to use new interfaces rosidl_python#51
• Linux-aarch64
  • unrelated test failures addressed in Update tests that were missed during switch to use new interfaces rosidl_python#51
• macOS
  • clang warnings: addressed in ros2/rosidl_typesupport_connext@43fccfd
  • unrelated test failures addressed in Update tests that were missed during switch to use new interfaces rosidl_python#51
• Windows
  • compiler warning:
    • 2 conversion warnings: addressed in ros2/rosidl_typesupport_connext@ea2e081
    • 2 inconsistent dll linkage warnings: addressed in ros2/rosidl_typesupport_fastrtps@6af2110
    • unrealted compiler warnings were addressed in Handle INT32_MIN value #375
  • linter warnings: addressed in use explicit encoding when reading files ament/ament_lint#138
  • known flaky test test_params_yaml
  • unrelated test failures addressed in Update tests that were missed during switch to use new interfaces rosidl_python#51

[jacobperron]

Looks like you've addressed all the warnings/failures. Considering you are adding more work on top of this, we can merge as-is and catch anything we missed in the next round of CI.

[dirk-thomas]

I went over all PRs again and resolved the remaining comments. In favor of time I will merge the changes now and trigger a set of CI builds afterwards to double check. 🤞

• Linux
• Linux-aarch64
• macOS
• Windows (aborted due to CI congestion)