[clang] [clang][ScanDeps] Use an options struct for the scanning service (PR #167964)

[Jan Svoboda via cfe-commits]

https://github.com/jansvoboda11 commented:

WDYT about making it so that the service only has a getter for the entire options object instead of for each of its fields? This way, when adding a new option you only need to edit `DependencyScanningServiceOptions` and the client, without touching `DependencyScanningService` itself.

https://github.com/llvm/llvm-project/pull/167964