Example iOS configuration not valid for TestFlight / deployment

[charypar]

I recently got an Crux iOS app into TestFlight and noticed that our example configurations need a few tweaks to pass the app validation stage

1. uniffi-bingen binary needs to be excluded from sources. With xcodegen that looks as follows

   settings:
     OTHER_LDFLAGS: [-w]
     SWIFT_OBJC_BRIDGING_HEADER: generated/sharedFFI.h
     ENABLE_USER_SCRIPT_SANDBOXING: NO
     "EXCLUDED_SOURCE_FILE_NAMES[arch=*]": "uniffi-bindgen"

2. In the build script which generates the FFI, we skip the step in an indexbuild phase, but we also need to skip it in the install buildphase, because the paths are all different, so the build fails, and it shouldn't run anyway
3. Step 1 might cover this, not sure, but we should generated the shared Xcode project with cargo xcode --skip-install, so that any binaries don't get bundled in the deployment archive (which makes it invalid as an app archive).