Improve PQ API

[Ngalstyan4]

• Add drop_quantization API that deletes all PQ-quantization resources associated with a table
• Add relevant hooks to make sure all quantization resources and table hooks are deleted when the lantern extension is deleted (table may already automatically get deleted since they are on _lantern_internal schema. we might need to do something for triggers though)
• qurrent api has quantize_vector but decompress_vector. switch to quantize/dequantize language
• make quantize_table work with all kinds of table names and formattings (currently not working when table name has mixed case. This method of quoting fixes regclass literal representation at callsite, but something is not properly escaped within the plpgsql function definition, so the call fails
• define pqvec casts in sql (pqvec to int array and int array to pqvec)
• allow quantizing subset of a table - will result in lower quality vectors but will speed up the process