Support include, from_env, from_zk

Why it matters

This feature enables more flexible and dynamic configuration of runtime disks by allowing inclusion of external configuration files (include), retrieving configuration values from environment variables (from_env), and fetching settings from ZooKeeper (from_zk). It enhances configuration management, making it easier to maintain and adapt disk settings without hardcoding values.

How to use it

Users can utilize the new options in the runtime disks configuration section of ClickHouse configuration files. They can apply <code>include</code> to import external configuration fragments, use <code>from_env</code> to load values from environment variables, and utilize <code>from_zk</code> to obtain configuration values from ZooKeeper nodes.