Add bit-packing

[a10y]

Currently I just split, dict-encode etc. Need to wire up bit-packing (and unpacking)

[mwlon]

Do I understand right that this still isn't exposed in the API? I'm hoping for some sort of function (or chain of functions) that take me from e.g. &[f32] -> Vec<u8>.

[robert3005]

For ALP-RD we need to bitpack te values which is not wired here yet. This is very specific to how ALP-RD is laid out internally and return type would be more complex than just Vec<u8>. Generally if your data is ALP encodeable you can run ALP on it and then use https://github.com/spiraldb/fastlanes for bitpacking. The full cascading compression is implemented in https://github.com/spiraldb/vortex/

[mwlon]

The split contains 5 things. Are you saying you apply fastlanes to each of them? I think a complete example is warranted