Support right-to-left layout on Windows

[abdnh]

What kind of change does this PR introduce?

This PR adds support for setting right-to-left layout on Windows using the WS_EX_LAYOUTRTL extended style and others. My main use for this is to make menus appear to the right in an Arabic app. I plan to add support for this to Tauri.

• Bugfix
• Feature
• Docs
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes
• No

Checklist

• This PR will resolve #___
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• I have added a convincing reason for adding this feature, if necessary
• It can be built on all targets and pass CI/CD.

Other information

[wusyong]

Let's make this platform-specific method if this is only for Windows.

[abdnh]

It should be possible to implement on Linux and macOS at least. I'll need macOS support in my app in the future so I might add that too then (currently don't have the time to investigate it and want to get Windows support merged as soon as possible).

Will make it a platform-specific method and add a .changes file.

[amrbashir]

Oh looks like you didn't sign your commits and I can't merge the PR unless they are signed. You need to setup commit signing, then you can sign past commit like this for example.

Seems like you also need to run cargo fmt

[abdnh]

Actually signed off the first commit and then forgot to sign the rest. Should be fine now I guess.