Introduce a new data type VECTOR (alias of ARRAY<Float32>)

[BohuTANG]

Summary

We propose adding a new data type, VECTOR, as an alias for ARRAY<FLOAT32>.

When a column type is set to VECTOR, an IVF_PQ index will be automatically created in the underlying storage.

This index significantly improves the speed and efficiency of cosine distance calculations, optimizing vector data retrieval and analysis.

[flaneur2020]

I guess the vector type may have a size hint? likewise VECTOR(1536)

On checking similiarities, the vectors' length should be same

[b41sh]

I guess the vector type may have a size hint? likewise VECTOR(1536)

On checking similiarities, the vectors' length should be same

Currently, there is no size_hint, we can add it later if needed.