internal/byteorder: new package

internal/byteorder: new package

Currently in a lot of packages we define functions for appending/decoding
mostly BigEndian data (see internal/chacha8rand, net/netip,
internal/boring/sha, hash/crc64, and probably more), because we don't
want to depend on encoding/binary, because of #54097.

This change introduces a new package internal/byteorder, that
will allow us to remove all of the functions and replace them with
internal/byteorder.

Updates #54097

Change-Id: I03e5ea1eb721dd98bdabdb25786f889cc5de54c5
GitHub-Last-Rev: 3f07d3dfb453a9e679395711f9b93e25f9340a3b
GitHub-Pull-Request: golang/go#67183
Reviewed-on: https://go-review.googlesource.com/c/go/+/583298
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Commit-Queue: Ian Lance Taylor <iant@golang.org>