Add iOS privacy manifests

[JohnSmith0922]

Description (What is the problem)

By Apple's Privacy manifest guidelines,
some action will be required such as adding an empty privacy manifests file even if you are not collecting anything.

Apple's document: https://developer.apple.com/documentation/bundleresources/privacy_manifest_files
See flutter/flutter#131940 for more context.

Solution suggestion

Add privacy manifests file (PrivacyInfo.xcprivacy) according to libraries privacy usage.

The following is an example of an empty privacy manifests file if this library is not collecting anything.
device_info_plus/ios/PrivacyInfo.xcprivacy

[Samo8]

When can we expect PrivacyInfo to be merged and new version release on pub.dev? The from Apple deadline is close. Thank you

[AlehSabadashGmail]

I am waiting too

[ryukukimura]

I'm also waiting for this to be merged.
Thanks for your great work!

[hk-kyon]

I am waiting too.