Support i128/u128 as NativePType

[a10y]

There are a number of suboptimal ways we treat VarBinView compute functions because we cannot support u128 as a native PType for PrimitiveArray

[robert3005]

FWIW I investigated it and the only weird thing is Arrow uses u128 and u256 only for Decimal arrays not for primitive ones. So those don't translate to arrow directly. Arrow workaround is to have a typed buffer that can be u128 but not array

[a10y]

Hmm, perhaps then VarBinView should hold the views in a Buffer rather than child array, side-steps that

[robert3005]

You could also do that just have to make sure it's properly aligned. I was thinking you could compress that view buffer but we can deal with it later

[gatesn]

I don't think we want this at the moment.