Add simulator destination and archivePath option

[TheNightmanCodeth]

I have a use-case for running archives for simulator destinations and passing the resulting archive to a different workflow.

This PR:

• adds the iOS-simulator option to platform field which sets the destination to generic/platform=iOS Simulator in the xcodebuild invocation
• adds archive-path setting to manually specify the path to output the .xcarchive result in archive builds

Please let me know if there's anything I can add or change.