Use cramjam to fill an allocated array with `uproot.AsDtypeInPlace`

[Jim Pivarski]

Actually, yes! One thing uproot is often doing is decompressing many small chunks and then concatenating them into a larger contiguous buffer. We could save some additional allocation and copy time if we can decompress into a buffer at an arbitrary offset.

Originally posted by @nsmith- in #1089 (comment)

If this has to bypass the basket_array concatenation, it is a big-project.