[ros2] Adding visibility control headers for Windows build

[seanyen]

• Adding visibility control headers for Windows build
• Defined _SILENCE_EXPERIMENTAL_FILESYSTEM_DEPRECATION_WARNING to ack the <experimental/filesystem> usage on MSVC. Otherwise, it manifests as a compile error.

[seanyen]

@jacobperron @mjcarroll This is ready for review and merge. Thanks.

[mjcarroll]

Defined _SILENCE_EXPERIMENTAL_FILESYSTEM_DEPRECATION_WARNING to ack the <experimental/filesystem> usage on MSVC. Otherwise, it manifests as a compile error.

Since this is coming from the rcpputils package, does it make sense to add that definition there rather than here?

[mjcarroll]

Everything else looks good once we determine where that compiler definition should go.

[mjcarroll]

Oh, I apologize, I thought that I had already landed #157 which removes the filesystem_helper.

Let me get that tested and in, then the define would probably make more sense in the rcpputils package.

[seanyen]

@mjcarroll Friendly ping.