NOTICE: binread -> binrw migration

Ok so to clarify some things:

* `binread` can still receive limited updates, however for the most part the 2.0.0 update is (in theory) the last major update to binread
* [`binrw`](https://github.com/jam1garner/binrw) is going to be where future development will likely be happening going forth
* binrw, while not entirely ready for use yet, is the preferred spot for PRs/Issues, however there is definitely an understanding that binrw might not progress at an acceptable rate for those who need things upstreamed, and if needed patches can be ported over pretty easily (in theory)

In case it isn't clear: binrw is a library designed to merge binread and binwrite while keeping a lot of the design choices of binread, and entirely reworking binwrite to better integrate with it.

While binrw is not a drop-in replacement for binread and will involve breaking changes, ease of migrating is something we're keeping in mind. If you're interested in being a part of the binrw design discussion, definitely join us on either [discord](https://discord.gg/ABy4Qh549j) or [matrix](https://matrix.to/#/#binrw:matrix.org) (both chats are bridged, so please choose whichever you feel more comfortable with)

This issue is a migration notice rather than an implementation task, and it names no files, tests, or code entry points. Read the linked binrw project first, then use the Discord or Matrix discussion for current design direction; there is no concrete completion criterion in this issue.

Written by the indexing model from the issue text.