The system-distributed-keyspace and view-update-generator often go in pair, because streaming, repair and sstables-loader (via distributed-loader) need them booth to check if sstable is staging and register it if it's such. The check is performed by messing directly with system_distributed.view_build_status table, and the registration happens via view-update-generator.
That's not nice, other services shouldn't know that view status is kept in system table. Also view-update-generator is a service to generae and push view updates, the fact that it keeps staging sstables list is the implementation detail.
This PR replaces dependencies on the mentioned pair of services with the single dependency on view-builder (repair, sstables-loader and stream-manager are enlightened) and hides the view building-vs-staging details inside the view_builder.
Along the way, some simplification of repair_writer_impl class is done.
Closesscylladb/scylladb#18706
* github.com:scylladb/scylladb:
stream_manager: Remove system_distributed_keyspace and view_update_generator
repair: Remove system_distributed_keyspace and view_update_generator
streaming: Remove system_distributed_keyspace and view_update_generator
sstables_loader: Remove system_distributed_keyspace and view_update_generator
distributed_loader: Remove system_distributed_keyspace and view_update_generator
view: Make register_staging_sstable() a method of view_builder
view: Make check_view_build_ongoing() helper a method of view_builder
streaming: Proparage view_builder& down to make_streaming_consumer()
repair: Keep view_builder& on repair_writer_impl
distributed_loader: Propagate view_builder& via process_upload_dir()
stream_manager: Add view builder dependency
repair_service: Add view builder dependency
sstables_loader: Add view_bulder dependency
main: Start sstables loader later
repair: Remove unwanted local references from repair_meta
47dbf23773