Cleanup Megazords ios + ios-rust directories

[data-sync-user]

After the full removal of carthage. We will have two folder paths in megazord both ios and ios-rust. iOS contains our xcodeproj and iOS tests while ios-rust contains our XCFramework and bundling scripts. There is some duplication shared there now with MozillaAppServices.h that can be removed and potentially look at merging the two folders into just one iOS folder

┆Issue is synchronized with this Jira Task ┆epic: local development, ci and release (backlog)