Remove chunk_cache from the WiredTiger public API configuration.

Changes needed:

• dist/api_data.py — remove wiredtiger_open_chunk_cache_configuration, connection_reconfigure_chunk_cache_configuration, chunk_cache_configuration_common, and the chunk_cache sub-key from io_capacity
• Run dist/s_all to regenerate src/config/config_def.c
• src/include/wiredtiger.h.in — remove any public chunk cache config documentation
• src/include/conf_keys.h — remove chunk cache conf key definitions

Acceptance criteria: passing chunk_cache=(...) to wiredtiger_open returns EINVAL: unknown configuration key.