[Parity] Integration the `--[auto|enable|disable]-index-store` option with SwiftBuild

[bkhouri]

The swift build --help has the following option

--auto-index-store/--enable-index-store/--disable-index-store
             Enable or disable indexing-while-building feature. (default: --auto-index-store)

SwiftBuild should have an API to set this option. Ensure SwiftPM supported this with SwiftBuild.