MariaDB Vector Store Integration: Add tuning parameters and utility functions (#17791)

...vector_stores/llama-index-vector-stores-mariadb/README.md

...-stores-mariadb/llama_index/vector_stores/mariadb/base.py

...r_stores/llama-index-vector-stores-mariadb/pyproject.toml

...ctor_stores/llama-index-vector-stores-mariadb/tests/BUILD

...s/llama-index-vector-stores-mariadb/tests/test_mariadb.py