Enhance the API to load and store vectors to and from `MemorySegment`s
as defined by [JEP 424: Foreign Function & Memory (FFM) API
(Preview)][JEP-424]. The FFM API is sufficiently mature that we are
comfortable adding this dependency to the Vector API. We will remove
equivalent API points that operate on `byte[]` and `ByteBuffer`, since
a `MemorySegment` can be obtained for either. Use of `MemorySegment`s
will enable the creation of *hyper-aligned* regions of memory, which
align to the byte length of a vector. On some architectures, such
alignment enables superior performance when loading and storing
vectors.