The timeout_config (more exactly -- updatable_timeout_config) is used by alternator/controller and transport/controller. Both create a local copy of that opbject by constructing one out of db::config. Also some options from this config are needed by storage_proxy, but since it doesn't have access to any timeout_config-s, it just uses db::config by getting it from the database.
This PR introduces top-level sharded<updateable_timeout_config>, initializes it from db::config values and makes existing users plus storage_proxy us it where required. Motivation -- remove more replica::database::get_config() users. A side effect -- timeout_config is not duplicated by transport and alternator controllers.
Components' dependencies cleanup, not backporting.
Closesscylladb/scylladb#29636
* github.com:scylladb/scylladb:
storage_proxy: Use shared updateable_timeout_config for CAS contention timeout
alternator: Use shared updateable_timeout_config by reference
cql_transport: Use shared updateable_timeout_config by reference
storage_proxy: Use shared updateable_timeout_config by reference
main: Introduce sharded<updateable_timeout_config>
storage_proxy: Keep own updateable_timeout_config
eae15f4fdd