Add Astro to Get Started with Workflow

[mrestrepoj10]

It would be great if Astro could also be included in the development process. :)

[pranaygp]

@mrestrepoj10 you wanna take a stab at this, based off the hono /nitro examples?
we're about to ship express/sveltekit really soon. also this guide might help - https://useworkflow.dev/docs/how-it-works/framework-integrations