Add context to Node SSR adapter

[laptou]

Changes

• Added a new property Astro.context which can be accessed by components and a new context property on the argument passed into endpoints
• This context can be set by passing a third parameter context into the handler in the Node.js adapter

Testing

• Added a unit test which verifies that the Astro.context global works as expected during SSR.

Docs

withastro/docs#1003

[changeset-bot]

🦋 Changeset detected

Latest commit: 09caf6e

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

This PR includes changesets to release 10 packages

Name	Type
astro	Minor
@astrojs/node	Minor
@e2e/astro-component	Patch
@e2e/lit-component	Patch
@e2e/preact-component	Patch
@e2e/react-component	Patch
@e2e/solid-component	Patch
@e2e/svelte-component	Patch
@e2e/e2e-tailwindcss	Patch
@e2e/ts-resolution	Patch

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[laptou]

The reason that I made these changes is that I want to integrate Astro SSR into an existing Koa.js server, and that server uses Passport.js for authentication. Astro SSR fits in neatly as a Koa middleware, but without a way to pass information to the Astro components from the server, its usefulness is limited (for example, I need to be able to pass in the authentication information that is provided by Passport, and it is not trivial to recalculate this information inside the Astro components).

[matthewp]

Thanks for submitting this! The RFC is here: withastro/roadmap#230 for anyone reading this.

Going to close this PR for now to keep the repo tidy. If the RFC is approved you can resubmit. Thanks again.