Enhance OneLake extension to support Iceberg tables

- Updated README.md to reflect support for Iceberg tables in addition to Delta tables.
- Introduced onelake_parser_extension.hpp and onelake_parser_extension.cpp to handle parsing and planning for Iceberg queries.
- Modified onelake_extension.cpp to register the new parser extension.
- Added functions to resolve and bind Iceberg scan functions in onelake_table_entry.cpp.
- Updated table discovery logic in onelake_table_set.cpp to detect and register Iceberg tables.
- Adjusted table entry creation to accommodate table format and relative location.
- Updated vcpkg submodule to the latest commit.