rename vectorize.table "table" parameter

[ChuckHend]

SELECT vectorize.table(
    job_name    => 'product_search_hf',
    "table"     => 'products',
    primary_key => 'product_id',
    columns     => ARRAY['product_name', 'description'],
    transformer => 'sentence-transformers/all-MiniLM-L6-v2',
    schedule    => 'realtime'
);

Having "table" as parameter causes a lot of issues for users. If the double quotes are missing the call will fail because table is a reserved word. We should rename that perhaps to "table_name" or "relation", and change the datatype to regclass. Idea with changing to regclass is that we will get more meaningful data validation errors if the table name provided does not exist, and I think using regclass would also mean we could remove the "schema" parameter.