feat: Workers Sites support for local mode

[threepointone]

There are 3 commits in this PR.

• One that adds a Workers Sites example, example-sites-app.
• Another that inlines text files into the Worker bundle directly (instead of adding them as 'modules' in the Worker definition)
• And another that implements the actual feature, where Workers Sites now works in local mode when running wrangler dev.

There are some bug fixes -

• fixes a bug where we were sending the __STATIC_CONTENT_MANIFEST definition as a separate module even with service worker format,
• fixes a bug where we weren't uploading the static content namespace binding when other kv namespaces weren't present.
• fixes an infinite fetching loop of KV namespace keys (also replicated in fix: prevent infinite loop when fetching a list of results #335, which will remove it from here after it lands)

[changeset-bot]

🦋 Changeset detected

Latest commit: 03dd897

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
wrangler	Patch

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[petebacondarwin]

I wondered whether the first commit needed a changeset. But then I realised that this will never be published, it is more of an example, than a package. So that made me think: perhaps example-worker-app and this new example-sites-app should not be in the packages directory at all??

Please can you add tests for the fixes to publish since that is possible right now. The dev fix is not so easy to test yet, so we can let that pass for now.