feat(flink-connector-ytsaurus & flink-yson): support dict and list types

[vovapraded]

Summary

Adds native YTsaurus dict, list, and single-level optional support for Flink MAP, ARRAY, and nullable types.

Supported

• Reading and writing YT dicts/lists as Flink maps/arrays, including recursive nesting.
• Non-consecutive optional<T> at any level: columns, list items, and dict values.
• On write, null is allowed only for optional YT types; on read, # is allowed only for nullable Flink types.
• Native scalar conversion inside nested types and validation of malformed dicts.

Limitations

• optional<optional<T>> is rejected because Flink nullability cannot represent all three YT states.
• Dict keys must be strings.
• Duplicate dict keys and entry order are not preserved.

[TheSeems]

The base solution looks good. Though we need more validation and account for nested maps/lists/arrays