feat: implement BinaryView and Utf8View in polars-arrow

[ritchie46]

The goal is to replace the current Arrow (Large)String type with a string type that allows a union between an inlined small string and an offset to a string that is allocated somewhere else.

This would prevent the terrible performance we have when filtering/gathering large string data as that forces a copy of all bytes. Second this type also allows string interning. As duplicates can only be stored once in the buffer and then we can point to that string multiple times.

Needless to say, still a lot to do.

Relevant arrow discussion here: https://lists.apache.org/thread/w88tpz76ox8h3rxkjl4so6rg3f1rv7wt
Whether or not they will go forward with this, we will.

It seems the BinView type is formally accepted in arrow! 🎉