Decrease web bundle size

[sgwilym]

What's the problem you want solved?

The bundle currently produced by make bundle is 300kb. A lot of this comes from dependencies. Part of Earthstar's strength is its lightness: our web bundle should reflect that.

Is there a solution you'd like to recommend?

Here's some low-hanging fruit:

• [x] Find an alternative to rfdc, which brings in Buffer from Deno's std/node library. (28 kb)
• [x] Update our fork of noble/ed25519 to not use an external sha512 library (32kb)
• [ ] Find an alternative to dbly-linked-list (also brought in transitively via concurrency-friends), which brings a lot of lodash code with it (24kb)

[sgwilym]

You can see the list of dependencies and their sizes using deno info mod.ts from the root of the project.