Change crypto library to get smaller browserify bundle

(Related: #3 Benchmark the crypto libraries)

The crypto needs of Earthstar can be filled by 2 swappable implementations so far:

cryptoChloride.ts - using chloride which chooses native or browser support as needed
cryptoNode.ts - using native node crypto

Chloride takes up 1.5mb when browserified.

We can

Try swapping it out for chloride/small which is probably slower, see the chloride readme for info
Add an implementation based on https://github.com/paulmillr/noble-ed25519 but converted to sync API

noble-ed25519 is nice -- small and pure JS -- but has an async API and we need a sync one. It's only async because it depends on a browser API to do sha512 async'ly. We could fork noble-25519 and make a sync version that depends on some other sha512 library.

We could also try some other crypto library such as sodium-universal. See https://github.com/cinnamon-bun/browser-crypto-diagram

The crypto backend is swappable here, but it's hardcoded: https://github.com/earthstar-project/earthstar/blob/master/src/crypto/crypto.ts#L1-L2

It would be better to let apps decide which one they wanted, and hopefully a tree-shaking bundler would know to omit the ones not being used.

earthstar-project / earthstar

Change crypto library to get smaller browserify bundle #4