[feat] Add a way to build iOS archives without signing #14940

Describe the problem

It would be good practice to have a way for CI/CD to build iOS .xcarchives without signing them, so that we can convert them to .ipa at a later stage and sign them offline (ourselves as developers or single users via AltStore et cetera). Currently, one can build via a combination of tauri ios build --open and launching xcodebuild from another terminal:

xcodebuild archive \
          -project gen/apple/${NAME}.xcodeproj \
          -scheme "${NAME}"_iOS \
          -archivePath gen/apple/build/App.xcarchive \
          -configuration Release
          CODE_SIGNING_REQUIRED=NO 
          CODE_SIGNING_ALLOWED=NO

Describe the solution you'd like

Something like tauri ios build --archive --no-codesign?

Alternatives considered

Making two concurrent jobs? Seems hard to do? I don't know

Additional context

Intended for use in GitHub Actions etc.