Bump Allocation

[yorickpeterse]

We need a chapter on allocating memory. I'm specifically thinking of bump allocation because:

1. It's super easy to implement
2. It delivers good performance
3. It can support concurrent and atomic operations, though you may still need locking in certain cases (e.g. when requesting a new arena to allocate into)

[yorickpeterse]

It's worth mentioning that this may require the use of the alloc crate, which currently still requires a nightly version of Rust. One can also use a Vec but that's a fairly limited approach and won't work if you want to store objects of different sizes (without using additional layers of indirection) or use a custom alignment.

[pliniker]

Re: alloc - I opened #9 for going over options.

[pliniker]

Basic single-threaded bump allocator ✔️