Initial --experimental-local implementation using Miniflare 3 (#1894)

* Initial `--experimental-local` implementation using Miniflare 3

* replace miniflare dynamic import with npx-import

* Update packages/wrangler/src/dev.tsx

Co-authored-by: Somhairle MacLeòid <samuel@macleod.space>

* Rename `experimentalMiniflare3` to `experimentalLocal`

* Remove reference to undefined `demandOneOfOption`

* Stub `caches` implementation when using `--experimental-local`

`workerd` currently throws on any use of the Cache API. Workers Sites
requires the Cache API to function though, so stub it out to no-ops,
like in regular `wrangler dev`.

* Ignore errors when cleaning up experimental local ref

These should've been caught/logged earlier.

* Add changeset

* Fix type errors

Co-authored-by: Cameron Robey <cameron@cameronrobey.co.uk>
Co-authored-by: Somhairle MacLeòid <samuel@macleod.space>

.changeset/short-candles-give.md

@@ -0,0 +1,7 @@
+---
+"wrangler": patch
+---
+
+Add experimental support for using the open-source Workers runtime [`workerd`](https://github.com/cloudflare/workerd) in `wrangler dev`.
+Use `wrangler dev --experimental-local` to try it out! 🚀
+Note this feature is still under active development.