feat: Index the (text) datasets contents to enable full-text search - DuckDB
First part for https://github.com/huggingface/datasets-server/issues/629 (index only)
New job runner to index parquet files at a split level using duckdb 
- Using parquet content, it will validate if there are string columns, if so, it will index all columns at least there is any image/audio/binary feature type (won't be supported yet since it could affect the viewer whenever search API is available, need a better design for this case).
- Will create a duckdb index file that contains the parquet + FTS search
- Will create a new branch duckdb/index in the dataset repository and upload the duckdb index file

feat: Index the (text) datasets contents to enable full-text search - DuckDB: First part for https://github.com/huggingface/datasets-server/issues/629 (index only)
New job runner to index parquet files at a split level using duckdb 
- Using parquet content, it will validate if there are string columns, if so, it will index all columns at least there is any image/audio/binary feature type (won't be supported yet since it could affect the viewer whenever search API is available, need a better design for this case).
- Will create a duckdb index file that contains the parquet + FTS search
- Will create a new branch duckdb/index in the dataset repository and upload the duckdb index file
